I would do it in PHP, except I would avoid doing preg_match 100 some times and do this to generate your list.

$tzlist = DateTimeZone::listIdentifiers(DateTimeZone::ALL);

Also, I would use PHP s names for the timezones and forget about GMT offsets, which will change based on DST. Code like that in phpbb is only that way b/c they are still supporting PHP4 and can t rely on the DateTime or DateTimeZone objects being there.

Following user210179 s example above, I ve written the following function to generate me a list of all timezones with their offsets:

function generate_timezone_list()
{
    static $regions = array(
        DateTimeZone::AFRICA,
        DateTimeZone::AMERICA,
        DateTimeZone::ANTARCTICA,
        DateTimeZone::ASIA,
        DateTimeZone::ATLANTIC,
        DateTimeZone::AUSTRALIA,
        DateTimeZone::EUROPE,
        DateTimeZone::INDIAN,
        DateTimeZone::PACIFIC,
    );

    $timezones = array();
    foreach( $regions as $region )
    {
        $timezones = array_merge( $timezones, DateTimeZone::listIdentifiers( $region ) );
    }

    $timezone_offsets = array();
    foreach( $timezones as $timezone )
    {
        $tz = new DateTimeZone($timezone);
        $timezone_offsets[$timezone] = $tz->getOffset(new DateTime);
    }

    // sort timezone by offset
    asort($timezone_offsets);

    $timezone_list = array();
    foreach( $timezone_offsets as $timezone => $offset )
    {
        $offset_prefix = $offset < 0 ?  -  :  + ;
        $offset_formatted = gmdate(  H:i , abs($offset) );

        $pretty_offset = "UTC${offset_prefix}${offset_formatted}";

        $timezone_list[$timezone] = "(${pretty_offset}) $timezone";
    }

    return $timezone_list;
}

This will generate an array looking like:

[Pacific/Midway] => (UTC-11:00) Pacific/Midway
[Pacific/Pago_Pago] => (UTC-11:00) Pacific/Pago_Pago
[Pacific/Niue] => (UTC-11:00) Pacific/Niue
[Pacific/Honolulu] => (UTC-10:00) Pacific/Honolulu
[Pacific/Fakaofo] => (UTC-10:00) Pacific/Fakaofo
…

It s currently sorted by offsets, but you can easily sort by the timezone name by doing a ksort() instead of asort().

Despite the number of existing answers, I ve made yet another solution to this problem. The pro s of my implementation are:

• The list of timezones is generated dynamically, and thus automatically updates when timezones might change (in PHP).
• Timezone names are prettified. For example, "America/St_Barthelemy" becomes "America, St. Barthelemy".
• Timezones are sorted on offset and name. Toland s answer only sorts on offset, resulting in unsorted groups of timezones within the same offset.
• Offset information is not retrieved from DateTimeZone::listAbbreviations, since that method also returns historical timezone information. Favio s answer does use this method, which results in incorrect (historical) offsets
• The list of timezones is only generated when first requested (and cached using a static variable).

Here is the full code:

function timezone_list() {
    static $timezones = null;

    if ($timezones === null) {
        $timezones = [];
        $offsets = [];
        $now = new DateTime( now , new DateTimeZone( UTC ));

        foreach (DateTimeZone::listIdentifiers() as $timezone) {
            $now->setTimezone(new DateTimeZone($timezone));
            $offsets[] = $offset = $now->getOffset();
            $timezones[$timezone] =  (  . format_GMT_offset($offset) .  )   . format_timezone_name($timezone);
        }

        array_multisort($offsets, $timezones);
    }

    return $timezones;
}

function format_GMT_offset($offset) {
    $hours = intval($offset / 3600);
    $minutes = abs(intval($offset % 3600 / 60));
    return  GMT  . ($offset ? sprintf( %+03d:%02d , $hours, $minutes) :   );
}

function format_timezone_name($name) {
    $name = str_replace( / ,  ,  , $name);
    $name = str_replace( _ ,    , $name);
    $name = str_replace( St  ,  St.  , $name);
    return $name;
}

And here s an example of the output

Array
(
    [Pacific/Midway]    => (GMT-11:00) Pacific, Midway
    [Pacific/Niue]      => (GMT-11:00) Pacific, Niue
    [Pacific/Pago_Pago] => (GMT-11:00) Pacific, Pago Pago
    [America/Adak]      => (GMT-10:00) America, Adak
    [Pacific/Honolulu]  => (GMT-10:00) Pacific, Honolulu
    [Pacific/Johnston]  => (GMT-10:00) Pacific, Johnston
    [Pacific/Rarotonga] => (GMT-10:00) Pacific, Rarotonga
    [Pacific/Tahiti]    => (GMT-10:00) Pacific, Tahiti
    [Pacific/Marquesas] => (GMT-09:30) Pacific, Marquesas
    [America/Anchorage] => (GMT-09:00) America, Anchorage
    ...
)

I would do it with the following code which is similar to the accepted answer (I m aware the code could be refactored :) ):

    $list = DateTimeZone::listAbbreviations();
    $idents = DateTimeZone::listIdentifiers();

    $data = $offset = $added = array();
    foreach ($list as $abbr => $info) {
        foreach ($info as $zone) {
            if ( ! empty($zone[ timezone_id ])
                AND
                ! in_array($zone[ timezone_id ], $added)
                AND 
                  in_array($zone[ timezone_id ], $idents)) {
                $z = new DateTimeZone($zone[ timezone_id ]);
                $c = new DateTime(null, $z);
                $zone[ time ] = $c->format( H:i a );
                $offset[] = $zone[ offset ] = $z->getOffset($c);
                $data[] = $zone;
                $added[] = $zone[ timezone_id ];
            }
        }
    }

    array_multisort($offset, SORT_ASC, $data);
    $options = array();
    foreach ($data as $key => $row) {
        $options[$row[ timezone_id ]] = $row[ time ] .   -  
                                        . formatOffset($row[ offset ]) 
                                        .     . $row[ timezone_id ];
    }

    // now you can use $options;

function formatOffset($offset) {
        $hours = $offset / 3600;
        $remainder = $offset % 3600;
        $sign = $hours > 0 ?  +  :  - ;
        $hour = (int) abs($hours);
        $minutes = (int) abs($remainder / 60);

        if ($hour == 0 AND $minutes == 0) {
            $sign =    ;
        }
        return  GMT  . $sign . str_pad($hour, 2,  0 , STR_PAD_LEFT) 
                . : . str_pad($minutes,2,  0 );

}

It produces something like:

<option value="America/Boise" label="02:10 am - GMT-06:00 America/Boise">02:10 am - GMT-06:00 America/Boise</option>

<option value="America/Denver" label="02:10 am - GMT-06:00 America/Denver">02:10 am - GMT-06:00 America/Denver</option>
<option value="America/Edmonton" label="02:10 am - GMT-06:00 America/Edmonton">02:10 am - GMT-06:00 America/Edmonton</option>
<option value="America/Inuvik" label="02:10 am - GMT-06:00 America/Inuvik">02:10 am - GMT-06:00 America/Inuvik</option>
<option value="America/Shiprock" label="02:10 am - GMT-06:00 America/Shiprock">02:10 am - GMT-06:00 America/Shiprock</option>

<option value="America/Belize" label="02:10 am - GMT-05:00 America/Belize">02:10 am - GMT-05:00 America/Belize</option>

Hope that helps a bit and/or inspire you to come with something better.

You can create very easy a dropdown from this array (It was a time-consuming task to put this together and test it). We already use this list in some of our apps.

It is very important to store timezone identifiers in your database and not just the timezone offset like "GMT+2", because of Daylight Saving Times.

UPDATE

I updated/corrected the timezones list (also checkout: https://github.com/paptamas/timezones):

<?php
$timezones = array (
 (GMT-11:00) Midway Island  =>  Pacific/Midway ,
 (GMT-11:00) Samoa  =>  Pacific/Samoa ,
 (GMT-10:00) Hawaii  =>  Pacific/Honolulu ,
 (GMT-09:00) Alaska  =>  US/Alaska ,
 (GMT-08:00) Pacific Time (US &amp; Canada)  =>  America/Los_Angeles ,
 (GMT-08:00) Tijuana  =>  America/Tijuana ,
 (GMT-07:00) Arizona  =>  US/Arizona ,
 (GMT-07:00) Chihuahua  =>  America/Chihuahua ,
 (GMT-07:00) La Paz  =>  America/Chihuahua ,
 (GMT-07:00) Mazatlan  =>  America/Mazatlan ,
 (GMT-07:00) Mountain Time (US &amp; Canada)  =>  US/Mountain ,
 (GMT-06:00) Central America  =>  America/Managua ,
 (GMT-06:00) Central Time (US &amp; Canada)  =>  US/Central ,
 (GMT-06:00) Guadalajara  =>  America/Mexico_City ,
 (GMT-06:00) Mexico City  =>  America/Mexico_City ,
 (GMT-06:00) Monterrey  =>  America/Monterrey ,
 (GMT-06:00) Saskatchewan  =>  Canada/Saskatchewan ,
 (GMT-05:00) Bogota  =>  America/Bogota ,
 (GMT-05:00) Eastern Time (US &amp; Canada)  =>  US/Eastern ,
 (GMT-05:00) Indiana (East)  =>  US/East-Indiana ,
 (GMT-05:00) Lima  =>  America/Lima ,
 (GMT-05:00) Quito  =>  America/Bogota ,
 (GMT-04:00) Atlantic Time (Canada)  =>  Canada/Atlantic ,
 (GMT-04:30) Caracas  =>  America/Caracas ,
 (GMT-04:00) La Paz  =>  America/La_Paz ,
 (GMT-04:00) Santiago  =>  America/Santiago ,
 (GMT-03:30) Newfoundland  =>  Canada/Newfoundland ,
 (GMT-03:00) Brasilia  =>  America/Sao_Paulo ,
 (GMT-03:00) Buenos Aires  =>  America/Argentina/Buenos_Aires ,
 (GMT-03:00) Georgetown  =>  America/Argentina/Buenos_Aires ,
 (GMT-03:00) Greenland  =>  America/Godthab ,
 (GMT-02:00) Mid-Atlantic  =>  America/Noronha ,
 (GMT-01:00) Azores  =>  Atlantic/Azores ,
 (GMT-01:00) Cape Verde Is.  =>  Atlantic/Cape_Verde ,
 (GMT+00:00) Casablanca  =>  Africa/Casablanca ,
 (GMT+00:00) Edinburgh  =>  Europe/London ,
 (GMT+00:00) Greenwich Mean Time : Dublin  =>  Etc/Greenwich ,
 (GMT+00:00) Lisbon  =>  Europe/Lisbon ,
 (GMT+00:00) London  =>  Europe/London ,
 (GMT+00:00) Monrovia  =>  Africa/Monrovia ,
 (GMT+00:00) UTC  =>  UTC ,
 (GMT+01:00) Amsterdam  =>  Europe/Amsterdam ,
 (GMT+01:00) Belgrade  =>  Europe/Belgrade ,
 (GMT+01:00) Berlin  =>  Europe/Berlin ,
 (GMT+01:00) Bern  =>  Europe/Berlin ,
 (GMT+01:00) Bratislava  =>  Europe/Bratislava ,
 (GMT+01:00) Brussels  =>  Europe/Brussels ,
 (GMT+01:00) Budapest  =>  Europe/Budapest ,
 (GMT+01:00) Copenhagen  =>  Europe/Copenhagen ,
 (GMT+01:00) Ljubljana  =>  Europe/Ljubljana ,
 (GMT+01:00) Madrid  =>  Europe/Madrid ,
 (GMT+01:00) Paris  =>  Europe/Paris ,
 (GMT+01:00) Prague  =>  Europe/Prague ,
 (GMT+01:00) Rome  =>  Europe/Rome ,
 (GMT+01:00) Sarajevo  =>  Europe/Sarajevo ,
 (GMT+01:00) Skopje  =>  Europe/Skopje ,
 (GMT+01:00) Stockholm  =>  Europe/Stockholm ,
 (GMT+01:00) Vienna  =>  Europe/Vienna ,
 (GMT+01:00) Warsaw  =>  Europe/Warsaw ,
 (GMT+01:00) West Central Africa  =>  Africa/Lagos ,
 (GMT+01:00) Zagreb  =>  Europe/Zagreb ,
 (GMT+02:00) Athens  =>  Europe/Athens ,
 (GMT+02:00) Bucharest  =>  Europe/Bucharest ,
 (GMT+02:00) Cairo  =>  Africa/Cairo ,
 (GMT+02:00) Harare  =>  Africa/Harare ,
 (GMT+02:00) Helsinki  =>  Europe/Helsinki ,
 (GMT+02:00) Istanbul  =>  Europe/Istanbul ,
 (GMT+02:00) Jerusalem  =>  Asia/Jerusalem ,
 (GMT+02:00) Kyiv  =>  Europe/Helsinki ,
 (GMT+02:00) Pretoria  =>  Africa/Johannesburg ,
 (GMT+02:00) Riga  =>  Europe/Riga ,
 (GMT+02:00) Sofia  =>  Europe/Sofia ,
 (GMT+02:00) Tallinn  =>  Europe/Tallinn ,
 (GMT+02:00) Vilnius  =>  Europe/Vilnius ,
 (GMT+03:00) Baghdad  =>  Asia/Baghdad ,
 (GMT+03:00) Kuwait  =>  Asia/Kuwait ,
 (GMT+03:00) Minsk  =>  Europe/Minsk ,
 (GMT+03:00) Nairobi  =>  Africa/Nairobi ,
 (GMT+03:00) Riyadh  =>  Asia/Riyadh ,
 (GMT+03:00) Volgograd  =>  Europe/Volgograd ,
 (GMT+03:30) Tehran  =>  Asia/Tehran ,
 (GMT+04:00) Abu Dhabi  =>  Asia/Muscat ,
 (GMT+04:00) Baku  =>  Asia/Baku ,
 (GMT+04:00) Moscow  =>  Europe/Moscow ,
 (GMT+04:00) Muscat  =>  Asia/Muscat ,
 (GMT+04:00) St. Petersburg  =>  Europe/Moscow ,
 (GMT+04:00) Tbilisi  =>  Asia/Tbilisi ,
 (GMT+04:00) Yerevan  =>  Asia/Yerevan ,
 (GMT+04:30) Kabul  =>  Asia/Kabul ,
 (GMT+05:00) Islamabad  =>  Asia/Karachi ,
 (GMT+05:00) Karachi  =>  Asia/Karachi ,
 (GMT+05:00) Tashkent  =>  Asia/Tashkent ,
 (GMT+05:30) Chennai  =>  Asia/Calcutta ,
 (GMT+05:30) Kolkata  =>  Asia/Kolkata ,
 (GMT+05:30) Mumbai  =>  Asia/Calcutta ,
 (GMT+05:30) New Delhi  =>  Asia/Calcutta ,
 (GMT+05:30) Sri Jayawardenepura  =>  Asia/Calcutta ,
 (GMT+05:45) Kathmandu  =>  Asia/Katmandu ,
 (GMT+06:00) Almaty  =>  Asia/Almaty ,
 (GMT+06:00) Astana  =>  Asia/Dhaka ,
 (GMT+06:00) Dhaka  =>  Asia/Dhaka ,
 (GMT+06:00) Ekaterinburg  =>  Asia/Yekaterinburg ,
 (GMT+06:30) Rangoon  =>  Asia/Rangoon ,
 (GMT+07:00) Bangkok  =>  Asia/Bangkok ,
 (GMT+07:00) Hanoi  =>  Asia/Bangkok ,
 (GMT+07:00) Jakarta  =>  Asia/Jakarta ,
 (GMT+07:00) Novosibirsk  =>  Asia/Novosibirsk ,
 (GMT+08:00) Beijing  =>  Asia/Hong_Kong ,
 (GMT+08:00) Chongqing  =>  Asia/Chongqing ,
 (GMT+08:00) Hong Kong  =>  Asia/Hong_Kong ,
 (GMT+08:00) Krasnoyarsk  =>  Asia/Krasnoyarsk ,
 (GMT+08:00) Kuala Lumpur  =>  Asia/Kuala_Lumpur ,
 (GMT+08:00) Perth  =>  Australia/Perth ,
 (GMT+08:00) Singapore  =>  Asia/Singapore ,
 (GMT+08:00) Taipei  =>  Asia/Taipei ,
 (GMT+08:00) Ulaan Bataar  =>  Asia/Ulan_Bator ,
 (GMT+08:00) Urumqi  =>  Asia/Urumqi ,
 (GMT+09:00) Irkutsk  =>  Asia/Irkutsk ,
 (GMT+09:00) Osaka  =>  Asia/Tokyo ,
 (GMT+09:00) Sapporo  =>  Asia/Tokyo ,
 (GMT+09:00) Seoul  =>  Asia/Seoul ,
 (GMT+09:00) Tokyo  =>  Asia/Tokyo ,
 (GMT+09:30) Adelaide  =>  Australia/Adelaide ,
 (GMT+09:30) Darwin  =>  Australia/Darwin ,
 (GMT+10:00) Brisbane  =>  Australia/Brisbane ,
 (GMT+10:00) Canberra  =>  Australia/Canberra ,
 (GMT+10:00) Guam  =>  Pacific/Guam ,
 (GMT+10:00) Hobart  =>  Australia/Hobart ,
 (GMT+10:00) Melbourne  =>  Australia/Melbourne ,
 (GMT+10:00) Port Moresby  =>  Pacific/Port_Moresby ,
 (GMT+10:00) Sydney  =>  Australia/Sydney ,
 (GMT+10:00) Yakutsk  =>  Asia/Yakutsk ,
 (GMT+11:00) Vladivostok  =>  Asia/Vladivostok ,
 (GMT+12:00) Auckland  =>  Pacific/Auckland ,
 (GMT+12:00) Fiji  =>  Pacific/Fiji ,
 (GMT+12:00) International Date Line West  =>  Pacific/Kwajalein ,
 (GMT+12:00) Kamchatka  =>  Asia/Kamchatka ,
 (GMT+12:00) Magadan  =>  Asia/Magadan ,
 (GMT+12:00) Marshall Is.  =>  Pacific/Fiji ,
 (GMT+12:00) New Caledonia  =>  Asia/Magadan ,
 (GMT+12:00) Solomon Is.  =>  Asia/Magadan ,
 (GMT+12:00) Wellington  =>  Pacific/Auckland ,
 (GMT+13:00) Nuku alofa  =>  Pacific/Tongatapu 
);
?>   

In some projects it really doesn t make sense to have the detailed timezones of Africa, Europe or Pacific. So here is a short version

$timezoneTable = array(
    "-12" => "(GMT -12:00) Eniwetok, Kwajalein",
    "-11" => "(GMT -11:00) Midway Island, Samoa",
    "-10" => "(GMT -10:00) Hawaii",
    "-9" => "(GMT -9:00) Alaska",
    "-8" => "(GMT -8:00) Pacific Time (US & Canada)",
    "-7" => "(GMT -7:00) Mountain Time (US & Canada)",
    "-6" => "(GMT -6:00) Central Time (US & Canada), Mexico City",
    "-5" => "(GMT -5:00) Eastern Time (US & Canada), Bogota, Lima",
    "-4" => "(GMT -4:00) Atlantic Time (Canada), Caracas, La Paz",
    "-3.5" => "(GMT -3:30) Newfoundland",
    "-3" => "(GMT -3:00) Brazil, Buenos Aires, Georgetown",
    "-2" => "(GMT -2:00) Mid-Atlantic",
    "-1" => "(GMT -1:00) Azores, Cape Verde Islands",
    "0" => "(GMT) Western Europe Time, London, Lisbon, Casablanca",
    "1" => "(GMT +1:00) Brussels, Copenhagen, Madrid, Paris",
    "2" => "(GMT +2:00) Kaliningrad, South Africa",
    "3" => "(GMT +3:00) Baghdad, Riyadh, Moscow, St. Petersburg",
    "3.5" => "(GMT +3:30) Tehran",
    "4" => "(GMT +4:00) Abu Dhabi, Muscat, Baku, Tbilisi",
    "4.5" => "(GMT +4:30) Kabul",
    "5" => "(GMT +5:00) Ekaterinburg, Islamabad, Karachi, Tashkent",
    "5.5" => "(GMT +5:30) Bombay, Calcutta, Madras, New Delhi",
    "6" => "(GMT +6:00) Almaty, Dhaka, Colombo",
    "7" => "(GMT +7:00) Bangkok, Hanoi, Jakarta",
    "8" => "(GMT +8:00) Beijing, Perth, Singapore, Hong Kong",
    "9" => "(GMT +9:00) Tokyo, Seoul, Osaka, Sapporo, Yakutsk",
    "9.5" => "(GMT +9:30) Adelaide, Darwin",
    "10" => "(GMT +10:00) Eastern Australia, Guam, Vladivostok",
    "11" => "(GMT +11:00) Magadan, Solomon Islands, New Caledonia",
    "12" => "(GMT +12:00) Auckland, Wellington, Fiji, Kamchatka"
);

echo "<select>";
foreach ($timezoneTable as $k => $v){
    $sel = ($k==-5)?" selected":"";
    echo "<option value= ".$k." ".$sel.">".$v."</option>";
}
echo "</select>" 

this will generate a select as below:

Here s one that creates a multidimensional array sorted by offset and niceified name:

function timezones() {
    $timezones = [];

    foreach (timezone_identifiers_list() as $timezone) {
        $datetime = new DateTime( now , new DateTimeZone($timezone));
        $timezones[] = [
             sort  => str_replace( : ,   , $datetime->format( P )),
             offset  => $datetime->format( P ),
             name  => str_replace( _ ,    , implode( ,  , explode( / , $timezone))),
             timezone  => $timezone,
        ];
    }

    usort($timezones, function($a, $b) {
        return $a[ sort ] - $b[ sort ] ?: strcmp($a[ name ], $b[ name ]);
    });

    return $timezones;
}

foreach (timezones() as $timezone) {
    echo  (UTC  .$timezone[ offset ]. )  .$timezone[ name ]. <br> ;
}

Echos:

(UTC -11:00) Pacific, Midway
(UTC -11:00) Pacific, Niue
(UTC -11:00) Pacific, Pago Pago
(UTC -10:00) Pacific, Honolulu
(UTC -10:00) Pacific, Johnston
(UTC -10:00) Pacific, Rarotonga
(UTC -10:00) Pacific, Tahiti
(UTC -09:30) Pacific, Marquesas
(UTC -09:00) America, Adak
(UTC -09:00) Pacific, Gambier
(UTC -08:00) America, Anchorage
(UTC -08:00) America, Juneau
...

Editing Tamas answer to remove all the "other" entries that the php.net site says should no longer be used.

Maybe doesn t matter, but just following best practices. See notice at bottom of: http://fr2.php.net/manual/en/timezones.others.php

Also, though this list has the Azores as GMT -1, in fact I think it s the same (at least sometimes) as GMT, but not sure.

Editing to offer this in sql so you can create the drop down list in a form and have the user s answer be tied to an index instead.

Editing again to remove leading space

CREATE TABLE IF NOT EXISTS `timezones` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(44) DEFAULT NULL,
  `timezone` varchar(30) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=141 ;

--
-- Dumping data for table `timezones`
--

INSERT INTO `timezones` (`id`, `name`, `timezone`) VALUES
(1,  (GMT-11:00) Midway Island  ,  Pacific/Midway ),
(2,  (GMT-11:00) Samoa  ,  Pacific/Samoa ),
(3,  (GMT-10:00) Hawaii  ,  Pacific/Honolulu ),
(4,  (GMT-09:00) Alaska  ,  America/Anchorage ),
(5,  (GMT-08:00) Pacific Time (US & Canada)  ,  America/Los_Angeles ),
(6,  (GMT-08:00) Tijuana  ,  America/Tijuana ),
(7,  (GMT-07:00) Chihuahua  ,  America/Chihuahua ),
(8,  (GMT-07:00) La Paz  ,  America/Chihuahua ),
(9,  (GMT-07:00) Mazatlan  ,  America/Mazatlan ),
(10,  (GMT-07:00) Mountain Time (US & Canada)  ,  America/Denver ),
(11,  (GMT-06:00) Central America  ,  America/Managua ),
(12,  (GMT-06:00) Central Time (US & Canada)  ,  America/Chicago ),
(13,  (GMT-06:00) Guadalajara  ,  America/Mexico_City ),
(14,  (GMT-06:00) Mexico City  ,  America/Mexico_City ),
(15,  (GMT-06:00) Monterrey  ,  America/Monterrey ),
(16,  (GMT-05:00) Bogota  ,  America/Bogota ),
(17,  (GMT-05:00) Eastern Time (US & Canada)  ,  America/New_York ),
(18,  (GMT-05:00) Lima  ,  America/Lima ),
(19,  (GMT-05:00) Quito  ,  America/Bogota ),
(20,  (GMT-04:00) Atlantic Time (Canada)  ,  Canada/Atlantic ),
(21,  (GMT-04:30) Caracas  ,  America/Caracas ),
(22,  (GMT-04:00) La Paz  ,  America/La_Paz ),
(23,  (GMT-04:00) Santiago  ,  America/Santiago ),
(24,  (GMT-03:30) Newfoundland  ,  America/St_Johns ),
(25,  (GMT-03:00) Brasilia  ,  America/Sao_Paulo ),
(26,  (GMT-03:00) Buenos Aires  ,  America/Argentina/Buenos_Aires ),
(27,  (GMT-03:00) Georgetown  ,  America/Argentina/Buenos_Aires ),
(28,  (GMT-03:00) Greenland  ,  America/Godthab ),
(29,  (GMT-02:00) Mid-Atlantic  ,  America/Noronha ),
(30,  (GMT-01:00) Azores  ,  Atlantic/Azores ),
(31,  (GMT-01:00) Cape Verde Is.  ,  Atlantic/Cape_Verde ),
(32,  (GMT+00:00) Casablanca  ,  Africa/Casablanca ),
(33,  (GMT+00:00) Edinburgh  ,  Europe/London ),
(34,  (GMT+00:00) Dublin  ,  Europe/Dublin ),
(35,  (GMT+00:00) Lisbon  ,  Europe/Lisbon ),
(36,  (GMT+00:00) London  ,  Europe/London ),
(37,  (GMT+00:00) Monrovia  ,  Africa/Monrovia ),
(38,  (GMT+00:00) UTC  ,  UTC ),
(39,  (GMT+01:00) Amsterdam  ,  Europe/Amsterdam ),
(40,  (GMT+01:00) Belgrade  ,  Europe/Belgrade ),
(41,  (GMT+01:00) Berlin  ,  Europe/Berlin ),
(42,  (GMT+01:00) Bern  ,  Europe/Berlin ),
(43,  (GMT+01:00) Bratislava  ,  Europe/Bratislava ),
(44,  (GMT+01:00) Brussels  ,  Europe/Brussels ),
(45,  (GMT+01:00) Budapest  ,  Europe/Budapest ),
(46,  (GMT+01:00) Copenhagen  ,  Europe/Copenhagen ),
(47,  (GMT+01:00) Ljubljana  ,  Europe/Ljubljana ),
(48,  (GMT+01:00) Madrid  ,  Europe/Madrid ),
(49,  (GMT+01:00) Paris  ,  Europe/Paris ),
(50,  (GMT+01:00) Prague  ,  Europe/Prague ),
(51,  (GMT+01:00) Rome  ,  Europe/Rome ),
(52,  (GMT+01:00) Sarajevo  ,  Europe/Sarajevo ),
(53,  (GMT+01:00) Skopje  ,  Europe/Skopje ),
(54,  (GMT+01:00) Stockholm  ,  Europe/Stockholm ),
(55,  (GMT+01:00) Vienna  ,  Europe/Vienna ),
(56,  (GMT+01:00) Warsaw  ,  Europe/Warsaw ),
(57,  (GMT+01:00) West Central Africa  ,  Africa/Lagos ),
(58,  (GMT+01:00) Zagreb  ,  Europe/Zagreb ),
(59,  (GMT+02:00) Athens  ,  Europe/Athens ),
(60,  (GMT+02:00) Bucharest  ,  Europe/Bucharest ),
(61,  (GMT+02:00) Cairo  ,  Africa/Cairo ),
(62,  (GMT+02:00) Harare  ,  Africa/Harare ),
(63,  (GMT+02:00) Helsinki  ,  Europe/Helsinki ),
(64,  (GMT+02:00) Istanbul  ,  Europe/Istanbul ),
(65,  (GMT+02:00) Jerusalem  ,  Asia/Jerusalem ),
(66,  (GMT+02:00) Kyiv  ,  Europe/Helsinki ),
(67,  (GMT+02:00) Pretoria  ,  Africa/Johannesburg ),
(68,  (GMT+02:00) Riga  ,  Europe/Riga ),
(69,  (GMT+02:00) Sofia  ,  Europe/Sofia ),
(70,  (GMT+02:00) Tallinn  ,  Europe/Tallinn ),
(71,  (GMT+02:00) Vilnius  ,  Europe/Vilnius ),
(72,  (GMT+03:00) Baghdad  ,  Asia/Baghdad ),
(73,  (GMT+03:00) Kuwait  ,  Asia/Kuwait ),
(74,  (GMT+03:00) Minsk  ,  Europe/Minsk ),
(75,  (GMT+03:00) Nairobi  ,  Africa/Nairobi ),
(76,  (GMT+03:00) Riyadh  ,  Asia/Riyadh ),
(77,  (GMT+03:00) Volgograd  ,  Europe/Volgograd ),
(78,  (GMT+03:30) Tehran  ,  Asia/Tehran ),
(79,  (GMT+04:00) Abu Dhabi  ,  Asia/Muscat ),
(80,  (GMT+04:00) Baku  ,  Asia/Baku ),
(81,  (GMT+04:00) Moscow  ,  Europe/Moscow ),
(82,  (GMT+04:00) Muscat  ,  Asia/Muscat ),
(83,  (GMT+04:00) St. Petersburg  ,  Europe/Moscow ),
(84,  (GMT+04:00) Tbilisi  ,  Asia/Tbilisi ),
(85,  (GMT+04:00) Yerevan  ,  Asia/Yerevan ),
(86,  (GMT+04:30) Kabul  ,  Asia/Kabul ),
(87,  (GMT+05:00) Islamabad  ,  Asia/Karachi ),
(88,  (GMT+05:00) Karachi  ,  Asia/Karachi ),
(89,  (GMT+05:00) Tashkent  ,  Asia/Tashkent ),
(90,  (GMT+05:30) Chennai  ,  Asia/Calcutta ),
(91,  (GMT+05:30) Kolkata  ,  Asia/Kolkata ),
(92,  (GMT+05:30) Mumbai  ,  Asia/Calcutta ),
(93,  (GMT+05:30) New Delhi  ,  Asia/Calcutta ),
(94,  (GMT+05:30) Sri Jayawardenepura  ,  Asia/Calcutta ),
(95,  (GMT+05:45) Kathmandu  ,  Asia/Katmandu ),
(96,  (GMT+06:00) Almaty  ,  Asia/Almaty ),
(97,  (GMT+06:00) Astana  ,  Asia/Dhaka ),
(98,  (GMT+06:00) Dhaka  ,  Asia/Dhaka ),
(99,  (GMT+06:00) Ekaterinburg  ,  Asia/Yekaterinburg ),
(100,  (GMT+06:30) Rangoon  ,  Asia/Rangoon ),
(101,  (GMT+07:00) Bangkok  ,  Asia/Bangkok ),
(102,  (GMT+07:00) Hanoi  ,  Asia/Bangkok ),
(103,  (GMT+07:00) Jakarta  ,  Asia/Jakarta ),
(104,  (GMT+07:00) Novosibirsk  ,  Asia/Novosibirsk ),
(105,  (GMT+08:00) Beijing  ,  Asia/Hong_Kong ),
(106,  (GMT+08:00) Chongqing  ,  Asia/Chongqing ),
(107,  (GMT+08:00) Hong Kong  ,  Asia/Hong_Kong ),
(108,  (GMT+08:00) Krasnoyarsk  ,  Asia/Krasnoyarsk ),
(109,  (GMT+08:00) Kuala Lumpur  ,  Asia/Kuala_Lumpur ),
(110,  (GMT+08:00) Perth  ,  Australia/Perth ),
(111,  (GMT+08:00) Singapore  ,  Asia/Singapore ),
(112,  (GMT+08:00) Taipei  ,  Asia/Taipei ),
(113,  (GMT+08:00) Ulaan Bataar  ,  Asia/Ulan_Bator ),
(114,  (GMT+08:00) Urumqi  ,  Asia/Urumqi ),
(115,  (GMT+09:00) Irkutsk  ,  Asia/Irkutsk ),
(116,  (GMT+09:00) Osaka  ,  Asia/Tokyo ),
(117,  (GMT+09:00) Sapporo  ,  Asia/Tokyo ),
(118,  (GMT+09:00) Seoul  ,  Asia/Seoul ),
(119,  (GMT+09:00) Tokyo  ,  Asia/Tokyo ),
(120,  (GMT+09:30) Adelaide  ,  Australia/Adelaide ),
(121,  (GMT+09:30) Darwin  ,  Australia/Darwin ),
(122,  (GMT+10:00) Brisbane  ,  Australia/Brisbane ),
(123,  (GMT+10:00) Canberra  ,  Australia/Canberra ),
(124,  (GMT+10:00) Guam  ,  Pacific/Guam ),
(125,  (GMT+10:00) Hobart  ,  Australia/Hobart ),
(126,  (GMT+10:00) Melbourne  ,  Australia/Melbourne ),
(127,  (GMT+10:00) Port Moresby  ,  Pacific/Port_Moresby ),
(128,  (GMT+10:00) Sydney  ,  Australia/Sydney ),
(129,  (GMT+10:00) Yakutsk  ,  Asia/Yakutsk ),
(130,  (GMT+11:00) Vladivostok  ,  Asia/Vladivostok ),
(131,  (GMT+12:00) Auckland  ,  Pacific/Auckland ),
(132,  (GMT+12:00) Fiji  ,  Pacific/Fiji ),
(133,  (GMT+12:00) International Date Line West  ,  Pacific/Kwajalein ),
(134,  (GMT+12:00) Kamchatka  ,  Asia/Kamchatka ),
(135,  (GMT+12:00) Magadan  ,  Asia/Magadan ),
(136,  (GMT+12:00) Marshall Is.  ,  Pacific/Fiji ),
(137,  (GMT+12:00) New Caledonia  ,  Asia/Magadan ),
(138,  (GMT+12:00) Solomon Is.  ,  Asia/Magadan ),
(139,  (GMT+12:00) Wellington  ,  Pacific/Auckland ),
(140,  (GMT+13:00) Nuku\alofa  ,  Pacific/Tongatapu );

/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;

I know this has an answer already but I saw an opportunity to improve upon one of the answers here. Toland H posted some very good code that does exactly what the question was asking for. Below is a shortened and expand version of Toland H s code:

• The function places everything in option tags for you. Just echo out whats return between your select tags.
• Major Improvement: The list is sorted first by continent and organized in option groups based on continents. Makes it very user friendly for visitors picking their timezone.

function generate_timezone_list() {
static $allRegions = array(
DateTimeZone::AFRICA,
DateTimeZone::AMERICA,
DateTimeZone::ANTARCTICA,
DateTimeZone::ASIA,
DateTimeZone::ATLANTIC,
DateTimeZone::AUSTRALIA,
DateTimeZone::EUROPE,
DateTimeZone::INDIAN,
DateTimeZone::PACIFIC
);
// Makes it easier to create option groups next
$list = array ( AFRICA , AMERICA , ANTARCTICA , ASIA , ATLANTIC , AUSTRALIA , EUROPE , INDIAN , PACIFIC );
// Make array holding the regions (continents), they are arrays w/ all their cities
$region = array();
foreach ($allRegions as $area){
array_push ($region,DateTimeZone::listIdentifiers( $area ));
}   
$count = count ($region); $i = 0; $holder =   ;
// Go through each region one by one, sorting and formatting it s cities
while ($i < $count){
$chunck = $region[$i];
// Create the region (continents) option group
$holder .=  <optgroup label="----------  .$list[$i].  ----------"> ;
$timezone_offsets = array();
foreach( $chunck as $timezone ){
$tz = new DateTimeZone($timezone);
$timezone_offsets[$timezone] = $tz->getOffset(new DateTime);
}
asort ($timezone_offsets);
$timezone_list = array();
foreach ($timezone_offsets as $timezone => $offset){
$offset_prefix = $offset < 0 ?  -  :  + ;
$offset_formatted = gmdate(  H:i , abs($offset) );
$pretty_offset = "UTC ${offset_prefix}${offset_formatted}";
$timezone_list[$timezone] = "(${pretty_offset}) $timezone";     
}
// All the formatting is done, finish and move on to next region
foreach ($timezone_list as $key => $val){
$holder .=  <option value=" .$key. "> .$val. </option> ;
}
$holder .=  </optgroup> ;
++$i;
}
return $holder;
}
echo "<select>".generate_timezone_list()."</select>";

Then all you need to do is echo out what is returned between your html select tags. You ll get a select list something like this:

----- AFRICA -----
(UTC +00:00) Africa/ city name
(UTC +01:00) Africa/ city name
(UTC +02:00) Africa/ city name
(UTC +02:00) Africa/ city name
----- AMERICA -----
(UTC -09:00) America/ city name
(UTC -07:00) America/ city name
(UTC +02:00) America/ city name
(UTC +05:00) America/ city name

And so on...

This riffs on the answer given by @Jonathan (fresh for 2021) and includes the javascript/jquery to auto select the time zone. The reason I like this is because a) it auto selects the users timezone, and b) if they want to change it they get a human readable alphabetically sorted list that makes it easy to scan for their country, and then city.

TBH, In most cases the user will not need to change it because it will correctly auto select with javasdcript.

PHP to build the picker data:

function timezonePickerData() {
    static $timezones = null;
    if ($timezones === null) {
        $timezones = [];
        $offsets = [];
        $now = new DateTime( now , new DateTimeZone( UTC ));
        foreach (DateTimeZone::listIdentifiers(DateTimeZone::ALL) as $timezone) {

            // Calculate offset
            $now->setTimezone(new DateTimeZone($timezone));
            $offsets[] = $offset = $now->getOffset();

            // Display text for UTC offset
            $hours = intval($offset / 3600);
            $minutes = abs(intval($offset % 3600 / 60));
            $utcDiff =  UTC  . ($offset ? sprintf( %+03d:%02d , $hours, $minutes) :   );

            // Display text for name
            $name = str_replace( / ,  ,  ,$timezone);
            $name = str_replace( _ ,    , $name);
            $name = str_replace( St  ,  St.  , $name);

            $timezones[$timezone] = "$name ($utcDiff)";
        }
    }

    return $timezones;
}

HTML/PHP to build the picker:

<select id="timezone">
<?php
    foreach(timezonePickerData() as $timezone => $location) {
        print "<option value="$timezone">$location</option>
";
    }
?>
</select>

jQuery to auto select the users timezone:

var data = Intl.DateTimeFormat().resolvedOptions()
$("#timezone").val(data.timeZone);

This is what the auto selected picker format looks like (un-clicked):

America, Los Angeles (UTC-7:00)

This is what the pick list looks like when the user clicks to change their timezone (easy for user to scan):

$timezone = array(
     Pacific/Midway  =>  (GMT-11:00) Midway Island, Samoa ,
     America/Adak  =>  (GMT-10:00) Hawaii-Aleutian ,
     Etc/GMT+10  =>  (GMT-10:00) Hawaii ,
     Pacific/Marquesas  =>  (GMT-09:30) Marquesas Islands ,
     Pacific/Gambier  =>  (GMT-09:00) Gambier Islands ,
     America/Anchorage  =>  (GMT-09:00) Alaska ,
     America/Ensenada  =>  (GMT-08:00) Tijuana, Baja California ,
     Etc/GMT+8  =>  (GMT-08:00) Pitcairn Islands ,
     America/Los_Angeles  =>  (GMT-08:00) Pacific Time (US & Canada) ,
     America/Denver  =>  (GMT-07:00) Mountain Time (US & Canada) ,
     America/Chihuahua  =>  (GMT-07:00) Chihuahua, La Paz, Mazatlan ,
     America/Dawson_Creek  =>  (GMT-07:00) Arizona ,
     America/Belize  =>  (GMT-06:00) Saskatchewan, Central America ,
     America/Cancun  =>  (GMT-06:00) Guadalajara, Mexico City, Monterrey ,
     Chile/EasterIsland  =>  (GMT-06:00) Easter Island ,
     America/Chicago  =>  (GMT-06:00) Central Time (US & Canada) ,
     America/New_York  =>  (GMT-05:00) Eastern Time (US & Canada) ,
     America/Havana  =>  (GMT-05:00) Cuba ,
     America/Bogota  =>  (GMT-05:00) Bogota, Lima, Quito, Rio Branco ,
     America/Caracas  =>  (GMT-04:30) Caracas ,
     America/Santiago  =>  (GMT-04:00) Santiago ,
     America/La_Paz  =>  (GMT-04:00) La Paz ,
     Atlantic/Stanley  =>  (GMT-04:00) Faukland Islands ,
     America/Campo_Grande  =>  (GMT-04:00) Brazil ,
     America/Goose_Bay  =>  (GMT-04:00) Atlantic Time (Goose Bay) ,
     America/Glace_Bay  =>  (GMT-04:00) Atlantic Time (Canada) ,
     America/St_Johns  =>  (GMT-03:30) Newfoundland ,
     America/Araguaina  =>  (GMT-03:00) UTC-3 ,
     America/Montevideo  =>  (GMT-03:00) Montevideo ,
     America/Miquelon  =>  (GMT-03:00) Miquelon, St. Pierre ,
     America/Godthab  =>  (GMT-03:00) Greenland ,
     America/Argentina/Buenos_Aires  =>  (GMT-03:00) Buenos Aires ,
     America/Sao_Paulo  =>  (GMT-03:00) Brasilia ,
     America/Noronha  =>  (GMT-02:00) Mid-Atlantic ,
     Atlantic/Cape_Verde  =>  (GMT-01:00) Cape Verde Is. ,
     Atlantic/Azores  =>  (GMT-01:00) Azores ,
     Europe/Belfast  =>  (GMT) Greenwich Mean Time : Belfast ,
     Europe/Dublin  =>  (GMT) Greenwich Mean Time : Dublin ,
     Europe/Lisbon  =>  (GMT) Greenwich Mean Time : Lisbon ,
     Europe/London  =>  (GMT) Greenwich Mean Time : London ,
     Africa/Abidjan  =>  (GMT) Monrovia, Reykjavik ,
     Europe/Amsterdam  =>  (GMT+01:00) Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna ,
     Europe/Belgrade  =>  (GMT+01:00) Belgrade, Bratislava, Budapest, Ljubljana, Prague ,
     Europe/Brussels  =>  (GMT+01:00) Brussels, Copenhagen, Madrid, Paris ,
     Africa/Algiers  =>  (GMT+01:00) West Central Africa ,
     Africa/Windhoek  =>  (GMT+01:00) Windhoek ,
     Asia/Beirut  =>  (GMT+02:00) Beirut ,
     Africa/Cairo  =>  (GMT+02:00) Cairo ,
     Asia/Gaza  =>  (GMT+02:00) Gaza ,
     Africa/Blantyre  =>  (GMT+02:00) Harare, Pretoria ,
     Asia/Jerusalem  =>  (GMT+02:00) Jerusalem ,
     Europe/Minsk  =>  (GMT+02:00) Minsk ,
     Asia/Damascus  =>  (GMT+02:00) Syria ,
     Europe/Moscow  =>  (GMT+03:00) Moscow, St. Petersburg, Volgograd ,
     Africa/Addis_Ababa  =>  (GMT+03:00) Nairobi ,
     Asia/Tehran  =>  (GMT+03:30) Tehran ,
     Asia/Dubai  =>  (GMT+04:00) Abu Dhabi, Muscat ,
     Asia/Yerevan  =>  (GMT+04:00) Yerevan ,
     Asia/Kabul  =>  (GMT+04:30) Kabul ,
     Asia/Yekaterinburg  =>  (GMT+05:00) Ekaterinburg ,
     Asia/Tashkent  =>  (GMT+05:00) Tashkent ,
     Asia/Kolkata  =>  (GMT+05:30) Chennai, Kolkata, Mumbai, New Delhi ,
     Asia/Katmandu  =>  (GMT+05:45) Kathmandu ,
     Asia/Dhaka  =>  (GMT+06:00) Astana, Dhaka ,
     Asia/Novosibirsk  =>  (GMT+06:00) Novosibirsk ,
     Asia/Rangoon  =>  (GMT+06:30) Yangon (Rangoon) ,
     Asia/Bangkok  =>  (GMT+07:00) Bangkok, Hanoi, Jakarta ,
     Asia/Krasnoyarsk  =>  (GMT+07:00) Krasnoyarsk ,
     Asia/Hong_Kong  =>  (GMT+08:00) Beijing, Chongqing, Hong Kong, Urumqi ,
     Asia/Irkutsk  =>  (GMT+08:00) Irkutsk, Ulaan Bataar ,
     Australia/Perth  =>  (GMT+08:00) Perth ,
     Australia/Eucla  =>  (GMT+08:45) Eucla ,
     Asia/Tokyo  =>  (GMT+09:00) Osaka, Sapporo, Tokyo ,
     Asia/Seoul  =>  (GMT+09:00) Seoul ,
     Asia/Yakutsk  =>  (GMT+09:00) Yakutsk ,
     Australia/Adelaide  =>  (GMT+09:30) Adelaide ,
     Australia/Darwin  =>  (GMT+09:30) Darwin ,
     Australia/Brisbane  =>  (GMT+10:00) Brisbane ,
     Australia/Hobart  =>  (GMT+10:00) Hobart ,
     Asia/Vladivostok  =>  (GMT+10:00) Vladivostok ,
     Australia/Lord_Howe  =>  (GMT+10:30) Lord Howe Island ,
     Etc/GMT-11  =>  (GMT+11:00) Solomon Is., New Caledonia ,
     Asia/Magadan  =>  (GMT+11:00) Magadan ,
     Pacific/Norfolk  =>  (GMT+11:30) Norfolk Island ,
     Asia/Anadyr  =>  (GMT+12:00) Anadyr, Kamchatka ,
     Pacific/Auckland  =>  (GMT+12:00) Auckland, Wellington ,
     Etc/GMT-12  =>  (GMT+12:00) Fiji, Kamchatka, Marshall Is. ,
     Pacific/Chatham  =>  (GMT+12:45) Chatham Islands ,
     Pacific/Tongatapu  =>  (GMT+13:00) Nukualofa ,
     Pacific/Kiritimati  =>  (GMT+14:00) Kiritimati ,

date_default_timezone_set($timezone);

Using listAbbreviations() makes no sense as for every area it returns all the different offsets that were historically used there, not just current ones. The right base source of the list is definitely listIdentifiers().

I would generate the list just once and save it to avoid generating it for every request. I could refresh it once a month.

Also, I could put all the timezones info into a separate js-script and generate the select list itself on the client side. The js-script could be cached as well, timezones don t change often.

Also, using javascript on the client side, you can know the current local time, and hence you can find the zones that have the same time now (minutes may differ, so comparison should be approximate), and display them on the top of the list, so the user does not have to scroll through all the 400 items. You can also display adjacent zones (+/-1 hour) following.

This PHP function do the Job for you an give back an array:

function time_zonelist(){
    $return = array();
    $timezone_identifiers_list = timezone_identifiers_list();
    foreach($timezone_identifiers_list as $timezone_identifier){
        $date_time_zone = new DateTimeZone($timezone_identifier);
        $date_time = new DateTime( now , $date_time_zone);
        $hours = floor($date_time_zone->getOffset($date_time) / 3600);
        $mins = floor(($date_time_zone->getOffset($date_time) - ($hours*3600)) / 60);
        $hours =  GMT  . ($hours < 0 ? $hours :  + .$hours);
        $mins = ($mins > 0 ? $mins :  0 .$mins);
        $text = str_replace("_"," ",$timezone_identifier);
        $return[$timezone_identifier] = $text.  ( .$hours. : .$mins. ) ;
    }
    return $return;
}

This PHP function give back an array of all existing Timezones including Offset:

Use it e.g. like this:

print_r(time_zonelist());

I wanted to have something simpler for my users, the way Google does it..

$timezones = [
    "AF" => [
        "name" => "Afghanistan" 
    ],
    "AL" => [
        "name" => "Albania" 
    ],
    "DZ" => [
        "name" => "Algeria" 
    ],
    "AS" => [
        "name" => "American Samoa" 
    ],
    "AD" => [
        "name" => "Andorra" 
    ],
    "AQ" => [
        "name" => "Antarctica" 
    ],
    "AG" => [
        "name" => "Antigua & Barbuda" 
    ],
    "AR" => [
        "name" => "Argentina" 
    ],
    "AM" => [
        "name" => "Armenia" 
    ],
    "AU" => [
        "name" => "Australia" 
    ],
    "AT" => [
        "name" => "Austria" 
    ],
    "AZ" => [
        "name" => "Azerbaijan" 
    ],
    "BS" => [
        "name" => "Bahamas" 
    ],
    "BD" => [
        "name" => "Bangladesh" 
    ],
    "BB" => [
        "name" => "Barbados" 
    ],
    "BY" => [
        "name" => "Belarus" 
    ],
    "BE" => [
        "name" => "Belgium" 
    ],
    "BZ" => [
        "name" => "Belize" 
    ],
    "BM" => [
        "name" => "Bermuda" 
    ],
    "BT" => [
        "name" => "Bhutan" 
    ],
    "BO" => [
        "name" => "Bolivia" 
    ],
    "BA" => [
        "name" => "Bosnia & Herzegovina" 
    ],
    "BR" => [
        "name" => "Brazil" 
    ],
    "IO" => [
        "name" => "British Indian Ocean Territory" 
    ],
    "BN" => [
        "name" => "Brunei" 
    ],
    "BG" => [
        "name" => "Bulgaria" 
    ],
    "CA" => [
        "name" => "Canada" 
    ],
    "CV" => [
        "name" => "Cape Verde" 
    ],
    "KY" => [
        "name" => "Cayman Islands" 
    ],
    "TD" => [
        "name" => "Chad" 
    ],
    "CL" => [
        "name" => "Chile" 
    ],
    "CN" => [
        "name" => "China" 
    ],
    "CX" => [
        "name" => "Christmas Island" 
    ],
    "CC" => [
        "name" => "Cocos (Keeling) Islands" 
    ],
    "CO" => [
        "name" => "Colombia" 
    ],
    "CK" => [
        "name" => "Cook Islands" 
    ],
    "CR" => [
        "name" => "Costa Rica" 
    ],
    "CI" => [
        "name" => "Côte d’Ivoire" 
    ],
    "HR" => [
        "name" => "Croatia" 
    ],
    "CU" => [
        "name" => "Cuba" 
    ],
    "CW" => [
        "name" => "Curaçao" 
    ],
    "CY" => [
        "name" => "Cyprus" 
    ],
    "CZ" => [
        "name" => "Czech Republic" 
    ],
    "DK" => [
        "name" => "Denmark" 
    ],
    "DO" => [
        "name" => "Dominican Republic" 
    ],
    "EC" => [
        "name" => "Ecuador" 
    ],
    "EG" => [
        "name" => "Egypt" 
    ],
    "SV" => [
        "name" => "El Salvador" 
    ],
    "EE" => [
        "name" => "Estonia" 
    ],
    "FK" => [
        "name" => "Falkland Islands (Islas Malvinas)" 
    ],
    "FO" => [
        "name" => "Faroe Islands" 
    ],
    "FJ" => [
        "name" => "Fiji" 
    ],
    "FI" => [
        "name" => "Finland" 
    ],
    "FR" => [
        "name" => "France" 
    ],
    "GF" => [
        "name" => "French Guiana" 
    ],
    "PF" => [
        "name" => "French Polynesia" 
    ],
    "TF" => [
        "name" => "French Southern Territories" 
    ],
    "GE" => [
        "name" => "Georgia" 
    ],
    "DE" => [
        "name" => "Germany" 
    ],
    "GH" => [
        "name" => "Ghana" 
    ],
    "GI" => [
        "name" => "Gibraltar" 
    ],
    "GR" => [
        "name" => "Greece" 
    ],
    "GL" => [
        "name" => "Greenland" 
    ],
    "GU" => [
        "name" => "Guam" 
    ],
    "GT" => [
        "name" => "Guatemala" 
    ],
    "GW" => [
        "name" => "Guinea-Bissau" 
    ],
    "GY" => [
        "name" => "Guyana" 
    ],
    "HT" => [
        "name" => "Haiti" 
    ],
    "HN" => [
        "name" => "Honduras" 
    ],
    "HK" => [
        "name" => "Hong Kong" 
    ],
    "HU" => [
        "name" => "Hungary" 
    ],
    "IS" => [
        "name" => "Iceland" 
    ],
    "IN" => [
        "name" => "India" 
    ],
    "ID" => [
        "name" => "Indonesia" 
    ],
    "IR" => [
        "name" => "Iran" 
    ],
    "IQ" => [
        "name" => "Iraq" 
    ],
    "IE" => [
        "name" => "Ireland" 
    ],
    "IL" => [
        "name" => "Israel" 
    ],
    "IT" => [
        "name" => "Italy" 
    ],
    "JM" => [
        "name" => "Jamaica" 
    ],
    "JP" => [
        "name" => "Japan" 
    ],
    "JO" => [
        "name" => "Jordan" 
    ],
    "KZ" => [
        "name" => "Kazakhstan" 
    ],
    "KE" => [
        "name" => "Kenya" 
    ],
    "KI" => [
        "name" => "Kiribati" 
    ],
    "KG" => [
        "name" => "Kyrgyzstan" 
    ],
    "LV" => [
        "name" => "Latvia" 
    ],
    "LB" => [
        "name" => "Lebanon" 
    ],
    "LR" => [
        "name" => "Liberia" 
    ],
    "LY" => [
        "name" => "Libya" 
    ],
    "LT" => [
        "name" => "Lithuania" 
    ],
    "LU" => [
        "name" => "Luxembourg" 
    ],
    "MO" => [
        "name" => "Macau" 
    ],
    "MK" => [
        "name" => "Macedonia (FYROM)" 
    ],
    "MY" => [
        "name" => "Malaysia" 
    ],
    "MV" => [
        "name" => "Maldives" 
    ],
    "MT" => [
        "name" => "Malta" 
    ],
    "MH" => [
        "name" => "Marshall Islands" 
    ],
    "MQ" => [
        "name" => "Martinique" 
    ],
    "MU" => [
        "name" => "Mauritius" 
    ],
    "MX" => [
        "name" => "Mexico" 
    ],
    "FM" => [
        "name" => "Micronesia" 
    ],
    "MD" => [
        "name" => "Moldova" 
    ],
    "MC" => [
        "name" => "Monaco" 
    ],
    "MN" => [
        "name" => "Mongolia" 
    ],
    "MA" => [
        "name" => "Morocco" 
    ],
    "MZ" => [
        "name" => "Mozambique" 
    ],
    "MM" => [
        "name" => "Myanmar (Burma)" 
    ],
    "NA" => [
        "name" => "Namibia" 
    ],
    "NR" => [
        "name" => "Nauru" 
    ],
    "NP" => [
        "name" => "Nepal" 
    ],
    "NL" => [
        "name" => "Netherlands" 
    ],
    "NC" => [
        "name" => "New Caledonia" 
    ],
    "NZ" => [
        "name" => "New Zealand" 
    ],
    "NI" => [
        "name" => "Nicaragua" 
    ],
    "NG" => [
        "name" => "Nigeria" 
    ],
    "NU" => [
        "name" => "Niue" 
    ],
    "NF" => [
        "name" => "Norfolk Island" 
    ],
    "KP" => [
        "name" => "North Korea" 
    ],
    "MP" => [
        "name" => "Northern Mariana Islands" 
    ],
    "NO" => [
        "name" => "Norway" 
    ],
    "PK" => [
        "name" => "Pakistan" 
    ],
    "PW" => [
        "name" => "Palau" 
    ],
    "PS" => [
        "name" => "Palestine" 
    ],
    "PA" => [
        "name" => "Panama" 
    ],
    "PG" => [
        "name" => "Papua New Guinea" 
    ],
    "PY" => [
        "name" => "Paraguay" 
    ],
    "PE" => [
        "name" => "Peru" 
    ],
    "PH" => [
        "name" => "Philippines" 
    ],
    "PN" => [
        "name" => "Pitcairn Islands" 
    ],
    "PL" => [
        "name" => "Poland" 
    ],
    "PT" => [
        "name" => "Portugal" 
    ],
    "PR" => [
        "name" => "Puerto Rico" 
    ],
    "QA" => [
        "name" => "Qatar" 
    ],
    "RE" => [
        "name" => "Réunion" 
    ],
    "RO" => [
        "name" => "Romania" 
    ],
    "RU" => [
        "name" => "Russia" 
    ],
    "WS" => [
        "name" => "Samoa" 
    ],
    "SM" => [
        "name" => "San Marino" 
    ],
    "SA" => [
        "name" => "Saudi Arabia" 
    ],
    "RS" => [
        "name" => "Serbia" 
    ],
    "SC" => [
        "name" => "Seychelles" 
    ],
    "SG" => [
        "name" => "Singapore" 
    ],
    "SK" => [
        "name" => "Slovakia" 
    ],
    "SI" => [
        "name" => "Slovenia" 
    ],
    "SB" => [
        "name" => "Solomon Islands" 
    ],
    "ZA" => [
        "name" => "South Africa" 
    ],
    "GS" => [
        "name" => "South Georgia & South Sandwich Islands" 
    ],
    "KR" => [
        "name" => "South Korea" 
    ],
    "ES" => [
        "name" => "Spain" 
    ],
    "LK" => [
        "name" => "Sri Lanka" 
    ],
    "PM" => [
        "name" => "St. Pierre & Miquelon" 
    ],
    "SD" => [
        "name" => "Sudan" 
    ],
    "SR" => [
        "name" => "Suriname" 
    ],
    "SJ" => [
        "name" => "Svalbard & Jan Mayen" 
    ],
    "SE" => [
        "name" => "Sweden" 
    ],
    "CH" => [
        "name" => "Switzerland" 
    ],
    "SY" => [
        "name" => "Syria" 
    ],
    "TW" => [
        "name" => "Taiwan" 
    ],
    "TJ" => [
        "name" => "Tajikistan" 
    ],
    "TH" => [
        "name" => "Thailand" 
    ],
    "TL" => [
        "name" => "Timor-Leste" 
    ],
    "TK" => [
        "name" => "Tokelau" 
    ],
    "TO" => [
        "name" => "Tonga" 
    ],
    "TT" => [
        "name" => "Trinidad & Tobago" 
    ],
    "TN" => [
        "name" => "Tunisia" 
    ],
    "TR" => [
        "name" => "Turkey" 
    ],
    "TM" => [
        "name" => "Turkmenistan" 
    ],
    "TC" => [
        "name" => "Turks & Caicos Islands" 
    ],
    "TV" => [
        "name" => "Tuvalu" 
    ],
    "UM" => [
        "name" => "U.S. Outlying Islands" 
    ],
    "UA" => [
        "name" => "Ukraine" 
    ],
    "AE" => [
        "name" => "United Arab Emirates" 
    ],
    "GB" => [
        "name" => "United Kingdom" 
    ],
    "US" => [
        "name" => "United States" 
    ],
    "UY" => [
        "name" => "Uruguay" 
    ],
    "UZ" => [
        "name" => "Uzbekistan" 
    ],
    "VU" => [
        "name" => "Vanuatu" 
    ],
    "VA" => [
        "name" => "Vatican City" 
    ],
    "VE" => [
        "name" => "Venezuela" 
    ],
    "VN" => [
        "name" => "Vietnam" 
    ],
    "WF" => [
        "name" => "Wallis & Futuna" 
    ],
    "EH" => [
        "name" => "Western Sahara" 
    ],
];

// taken from Toland Hon s Answer
function prettyOffset($offset) {
    $offset_prefix = $offset < 0 ?  -  :  + ;
    $offset_formatted = gmdate(  H:i , abs($offset) );

    $pretty_offset = "UTC${offset_prefix}${offset_formatted}";

    return $pretty_offset;
}

foreach ($timezones as $k => $v) {
    $tz = DateTimeZone::listIdentifiers(DateTimeZone::PER_COUNTRY, $k);

    foreach ($tz as $value) {
        $t = new DateTimeZone($value);
        $offset = (new DateTime("now", $t))->getOffset();
        $timezones[$k][ timezones ][$value] = prettyOffset($offset);
    }   
}

This gives me an array grouped by countries:

["US"]=>
  array(2) {
    ["name"]=>
    string(13) "United States"
    ["timezones"]=>
    array(29) {
      ["America/Adak"]=>
      string(9) "UTC-10:00"
      ["America/Anchorage"]=>
      string(9) "UTC-09:00"
      ["America/Boise"]=>
      string(9) "UTC-07:00"
      ["America/Chicago"]=>
      string(9) "UTC-06:00"
      ["America/Denver"]=>
      string(9) "UTC-07:00"
      ["America/Detroit"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Indianapolis"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Knox"]=>
      string(9) "UTC-06:00"
      ["America/Indiana/Marengo"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Petersburg"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Tell_City"]=>
      string(9) "UTC-06:00"
      ["America/Indiana/Vevay"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Vincennes"]=>
      string(9) "UTC-05:00"
      ["America/Indiana/Winamac"]=>
      string(9) "UTC-05:00"
      ["America/Juneau"]=>
      string(9) "UTC-09:00"
      ["America/Kentucky/Louisville"]=>
      string(9) "UTC-05:00"
      ["America/Kentucky/Monticello"]=>
      string(9) "UTC-05:00"
      ["America/Los_Angeles"]=>
      string(9) "UTC-08:00"
      ["America/Menominee"]=>
      string(9) "UTC-06:00"
      ["America/Metlakatla"]=>
      string(9) "UTC-08:00"
      ["America/New_York"]=>
      string(9) "UTC-05:00"
      ["America/Nome"]=>
      string(9) "UTC-09:00"
      ["America/North_Dakota/Beulah"]=>
      string(9) "UTC-06:00"
      ["America/North_Dakota/Center"]=>
      string(9) "UTC-06:00"
      ["America/North_Dakota/New_Salem"]=>
      string(9) "UTC-06:00"
      ["America/Phoenix"]=>
      string(9) "UTC-07:00"
      ["America/Sitka"]=>
      string(9) "UTC-09:00"
      ["America/Yakutat"]=>
      string(9) "UTC-09:00"
      ["Pacific/Honolulu"]=>
      string(9) "UTC-10:00"
    }
  }

Which means now I can do something like below (of course with some javaScript trickery):

public static function tzList()
{
    $tzMap = array();
    $zones = DateTimeZone::listIdentifiers();
    foreach ($zones as $zone) {
        $tz = new DateTimeZone($zone);
        $now = new DateTime("utc", $tz);
        $diffInSeconds = $tz->getOffset($now);
        $hours = floor($diffInSeconds / 3600);
        $minutes = floor(($diffInSeconds % 3600) / 60);
        $tzMap[$zone] = sprintf("%+d", $hours) . ":" . sprintf("%02d", $minutes);
    }
    return $tzMap;
}

Tada! It s this simple. Gives you an array with the key as the PHP timezone and the value as a string in the format +-Hours:Minutes

I created a PHP class for this with a corresponding jQuery plugin. I ve open-sourced it at https://github.com/peterjtracey/timezoneWidget - the PHP code is inspired by another stackoverflow answer, but I think much more elegant. The jQuery plugin gives a great interface for selecting a timezone.

Variant 1

Result:

...
[America/Scoresbysund] => (UTC+00:00) America/Scoresbysund
[Atlantic/Azores] => (UTC+00:00) Atlantic/Azores
[Atlantic/Reykjavik] => (UTC+00:00) Atlantic/Reykjavik
[Atlantic/St_Helena] => (UTC+00:00) Atlantic/St_Helena
[UTC] => (UTC+00:00) UTC
[Africa/Algiers] => (UTC+01:00) Africa/Algiers
[Africa/Bangui] => (UTC+01:00) Africa/Bangui 
...

Code:

$tzlist = DateTimeZone::listIdentifiers(DateTimeZone::ALL);

$result = [];
foreach ($tzlist as $timezone) {
    $offset = (new DateTimeZone($timezone))->getOffset(new DateTime);
    $offsetPrefix = $offset < 0 ?  -  :  + ;
    $offsetFormatted = gmdate( H:i , abs($offset));
    $utcOffset = "(UTC$offsetPrefix$offsetFormatted)";

    $result[$timezone] = "${$utcOffset} $timezone";
}
asort($result);
print_r($result);

Variant 2

Result:

Array
(
    [0] => Array
        (
            [value] => Africa/Abidjan
            [offset] => +00:00
            [text] => (UTC+00:00) Africa/Abidjan
        )

    [1] => Array
        (
            [value] => Africa/Conakry
            [offset] => +00:00
            [text] => (UTC+00:00) Africa/Conakry
        )
...

Code:

$tzlist = DateTimeZone::listIdentifiers(DateTimeZone::ALL);

$result = [];
foreach ($tzlist as $timezone) {
    $offset = (new DateTimeZone($timezone))->getOffset(new DateTime);
    $offsetPrefix = $offset < 0 ?  -  :  + ;
    $offsetFormatted = gmdate( H:i , abs($offset));
    $utcOffset = "UTC$offsetPrefix$offsetFormatted";

    $result[] = [
         value  => $timezone,
         offset  => "$offsetPrefix$offsetFormatted"
        // "text" => "($utcOffset) $timezone"
    ];
}
usort($result, function ($a, $b) { return strcmp($a["offset"], $b["offset"]); });
print_r($result);

If you don t want to be dependent on static timezone list, or want to display the offset along with timezone.

Here is what I came up with

function timezones()
{
    $timezones = DateTimeZone::listIdentifiers();
    $items = array();
    foreach($timezones as $timezoneId) {
        $timezone = new DateTimeZone($timezoneId);
        $offsetInSeconds = $timezone->getOffset(new DateTime());
        $items[$timezoneId] = $offsetInSeconds;
    }
    asort($items);
    array_walk ($items, function (&$offsetInSeconds, &$timezoneId) { 
        $offsetPrefix = $offsetInSeconds < 0 ?  -  :  + ;
        $offset = gmdate( H:i , abs($offsetInSeconds));
        $offset = "(GMT${offsetPrefix}${offset}) ".$timezoneId;
        $offsetInSeconds = $offset;
    });
    return $items;
}

Which gives me the following result

Array
(
    [Pacific/Midway] => (GMT-11:00) Pacific/Midway
    [Pacific/Pago_Pago] => (GMT-11:00) Pacific/Pago_Pago
    [Pacific/Niue] => (GMT-11:00) Pacific/Niue
    [America/Adak] => (GMT-10:00) America/Adak
    [Pacific/Tahiti] => (GMT-10:00) Pacific/Tahiti
    [Pacific/Rarotonga] => (GMT-10:00) Pacific/Rarotonga
    [Pacific/Honolulu] => (GMT-10:00) Pacific/Honolulu
    [Pacific/Marquesas] => (GMT-09:30) Pacific/Marquesas
    [America/Sitka] => (GMT-09:00) America/Sitka
    [Pacific/Gambier] => (GMT-09:00) Pacific/Gambier
    [America/Yakutat] => (GMT-09:00) America/Yakutat
    [America/Juneau] => (GMT-09:00) America/Juneau
    [America/Nome] => (GMT-09:00) America/Nome
    [America/Anchorage] => (GMT-09:00) America/Anchorage
    [America/Metlakatla] => (GMT-09:00) America/Metlakatla
    [America/Los_Angeles] => (GMT-08:00) America/Los_Angeles
    [America/Tijuana] => (GMT-08:00) America/Tijuana
    [America/Whitehorse] => (GMT-08:00) America/Whitehorse
    [America/Vancouver] => (GMT-08:00) America/Vancouver
    [America/Dawson] => (GMT-08:00) America/Dawson
    [Pacific/Pitcairn] => (GMT-08:00) Pacific/Pitcairn
    [America/Mazatlan] => (GMT-07:00) America/Mazatlan
    [America/Fort_Nelson] => (GMT-07:00) America/Fort_Nelson
    [America/Yellowknife] => (GMT-07:00) America/Yellowknife
    [America/Inuvik] => (GMT-07:00) America/Inuvik
    [America/Edmonton] => (GMT-07:00) America/Edmonton
    [America/Denver] => (GMT-07:00) America/Denver
    [America/Chihuahua] => (GMT-07:00) America/Chihuahua
    [America/Boise] => (GMT-07:00) America/Boise
    [America/Ojinaga] => (GMT-07:00) America/Ojinaga
    [America/Cambridge_Bay] => (GMT-07:00) America/Cambridge_Bay
    [America/Dawson_Creek] => (GMT-07:00) America/Dawson_Creek
    [America/Phoenix] => (GMT-07:00) America/Phoenix
    [America/Hermosillo] => (GMT-07:00) America/Hermosillo
    [America/Creston] => (GMT-07:00) America/Creston
    [America/Matamoros] => (GMT-06:00) America/Matamoros
    [America/Menominee] => (GMT-06:00) America/Menominee
    [America/Indiana/Knox] => (GMT-06:00) America/Indiana/Knox
    [America/Managua] => (GMT-06:00) America/Managua
    [America/Bahia_Banderas] => (GMT-06:00) America/Bahia_Banderas
    [America/Indiana/Tell_City] => (GMT-06:00) America/Indiana/Tell_City
    [America/Belize] => (GMT-06:00) America/Belize
    [America/Chicago] => (GMT-06:00) America/Chicago
    [America/Guatemala] => (GMT-06:00) America/Guatemala
    [America/El_Salvador] => (GMT-06:00) America/El_Salvador
    [America/Merida] => (GMT-06:00) America/Merida
    [America/Costa_Rica] => (GMT-06:00) America/Costa_Rica
    [America/Mexico_City] => (GMT-06:00) America/Mexico_City
    [America/Winnipeg] => (GMT-06:00) America/Winnipeg
    [Pacific/Galapagos] => (GMT-06:00) Pacific/Galapagos
    [America/Resolute] => (GMT-06:00) America/Resolute
    [America/Regina] => (GMT-06:00) America/Regina
    [America/Rankin_Inlet] => (GMT-06:00) America/Rankin_Inlet
    [America/Rainy_River] => (GMT-06:00) America/Rainy_River
    [America/North_Dakota/New_Salem] => (GMT-06:00) America/North_Dakota/New_Salem
    [America/North_Dakota/Beulah] => (GMT-06:00) America/North_Dakota/Beulah
    [America/North_Dakota/Center] => (GMT-06:00) America/North_Dakota/Center
    [America/Tegucigalpa] => (GMT-06:00) America/Tegucigalpa
    [America/Swift_Current] => (GMT-06:00) America/Swift_Current
    [America/Monterrey] => (GMT-06:00) America/Monterrey
    [America/Pangnirtung] => (GMT-05:00) America/Pangnirtung
    [America/Indiana/Petersburg] => (GMT-05:00) America/Indiana/Petersburg
    [America/Indiana/Marengo] => (GMT-05:00) America/Indiana/Marengo
    [America/Bogota] => (GMT-05:00) America/Bogota
    [America/Toronto] => (GMT-05:00) America/Toronto
    [America/Detroit] => (GMT-05:00) America/Detroit
    [America/Panama] => (GMT-05:00) America/Panama
    [America/Cancun] => (GMT-05:00) America/Cancun
    [America/Rio_Branco] => (GMT-05:00) America/Rio_Branco
    [America/Port-au-Prince] => (GMT-05:00) America/Port-au-Prince
    [America/Cayman] => (GMT-05:00) America/Cayman
    [America/Grand_Turk] => (GMT-05:00) America/Grand_Turk
    [America/Havana] => (GMT-05:00) America/Havana
    [America/Indiana/Indianapolis] => (GMT-05:00) America/Indiana/Indianapolis
    [America/Indiana/Vevay] => (GMT-05:00) America/Indiana/Vevay
    [America/Guayaquil] => (GMT-05:00) America/Guayaquil
    [America/Nipigon] => (GMT-05:00) America/Nipigon
    [America/Indiana/Vincennes] => (GMT-05:00) America/Indiana/Vincennes
    [America/Atikokan] => (GMT-05:00) America/Atikokan
    [America/Indiana/Winamac] => (GMT-05:00) America/Indiana/Winamac
    [America/New_York] => (GMT-05:00) America/New_York
    [America/Iqaluit] => (GMT-05:00) America/Iqaluit
    [America/Jamaica] => (GMT-05:00) America/Jamaica
    [America/Nassau] => (GMT-05:00) America/Nassau
    [America/Kentucky/Louisville] => (GMT-05:00) America/Kentucky/Louisville
    [America/Kentucky/Monticello] => (GMT-05:00) America/Kentucky/Monticello
    [America/Eirunepe] => (GMT-05:00) America/Eirunepe
    [Pacific/Easter] => (GMT-05:00) Pacific/Easter
    [America/Lima] => (GMT-05:00) America/Lima
    [America/Thunder_Bay] => (GMT-05:00) America/Thunder_Bay
    [America/Guadeloupe] => (GMT-04:00) America/Guadeloupe
    [America/Manaus] => (GMT-04:00) America/Manaus
    [America/Guyana] => (GMT-04:00) America/Guyana
    [America/Halifax] => (GMT-04:00) America/Halifax
    [America/Puerto_Rico] => (GMT-04:00) America/Puerto_Rico
    [America/Porto_Velho] => (GMT-04:00) America/Porto_Velho
    [America/Port_of_Spain] => (GMT-04:00) America/Port_of_Spain
    [America/Montserrat] => (GMT-04:00) America/Montserrat
    [America/Moncton] => (GMT-04:00) America/Moncton
    [America/Martinique] => (GMT-04:00) America/Martinique
    [America/Kralendijk] => (GMT-04:00) America/Kralendijk
    [America/La_Paz] => (GMT-04:00) America/La_Paz
    [America/Marigot] => (GMT-04:00) America/Marigot
    [America/Lower_Princes] => (GMT-04:00) America/Lower_Princes
    [America/Grenada] => (GMT-04:00) America/Grenada
    [America/Santo_Domingo] => (GMT-04:00) America/Santo_Domingo
    [America/Goose_Bay] => (GMT-04:00) America/Goose_Bay
    [America/Caracas] => (GMT-04:00) America/Caracas
    [America/Anguilla] => (GMT-04:00) America/Anguilla
    [America/St_Barthelemy] => (GMT-04:00) America/St_Barthelemy
    [America/Barbados] => (GMT-04:00) America/Barbados
    [America/St_Kitts] => (GMT-04:00) America/St_Kitts
    [America/Blanc-Sablon] => (GMT-04:00) America/Blanc-Sablon
    [America/Boa_Vista] => (GMT-04:00) America/Boa_Vista
    [America/St_Lucia] => (GMT-04:00) America/St_Lucia
    [America/St_Thomas] => (GMT-04:00) America/St_Thomas
    [America/Antigua] => (GMT-04:00) America/Antigua
    [America/St_Vincent] => (GMT-04:00) America/St_Vincent
    [America/Thule] => (GMT-04:00) America/Thule
    [America/Curacao] => (GMT-04:00) America/Curacao
    [America/Tortola] => (GMT-04:00) America/Tortola
    [America/Dominica] => (GMT-04:00) America/Dominica
    [Atlantic/Bermuda] => (GMT-04:00) Atlantic/Bermuda
    [America/Glace_Bay] => (GMT-04:00) America/Glace_Bay
    [America/Aruba] => (GMT-04:00) America/Aruba
    [America/St_Johns] => (GMT-03:30) America/St_Johns
    [America/Argentina/Tucuman] => (GMT-03:00) America/Argentina/Tucuman
    [America/Belem] => (GMT-03:00) America/Belem
    [America/Santiago] => (GMT-03:00) America/Santiago
    [America/Santarem] => (GMT-03:00) America/Santarem
    [America/Recife] => (GMT-03:00) America/Recife
    [America/Punta_Arenas] => (GMT-03:00) America/Punta_Arenas
    [Atlantic/Stanley] => (GMT-03:00) Atlantic/Stanley
    [America/Paramaribo] => (GMT-03:00) America/Paramaribo
    [America/Fortaleza] => (GMT-03:00) America/Fortaleza
    [America/Argentina/San_Luis] => (GMT-03:00) America/Argentina/San_Luis
    [Antarctica/Palmer] => (GMT-03:00) Antarctica/Palmer
    [America/Montevideo] => (GMT-03:00) America/Montevideo
    [America/Cuiaba] => (GMT-03:00) America/Cuiaba
    [America/Miquelon] => (GMT-03:00) America/Miquelon
    [America/Cayenne] => (GMT-03:00) America/Cayenne
    [America/Campo_Grande] => (GMT-03:00) America/Campo_Grande
    [Antarctica/Rothera] => (GMT-03:00) Antarctica/Rothera
    [America/Godthab] => (GMT-03:00) America/Godthab
    [America/Bahia] => (GMT-03:00) America/Bahia
    [America/Asuncion] => (GMT-03:00) America/Asuncion
    [America/Argentina/Ushuaia] => (GMT-03:00) America/Argentina/Ushuaia
    [America/Argentina/La_Rioja] => (GMT-03:00) America/Argentina/La_Rioja
    [America/Araguaina] => (GMT-03:00) America/Araguaina
    [America/Argentina/Buenos_Aires] => (GMT-03:00) America/Argentina/Buenos_Aires
    [America/Argentina/Rio_Gallegos] => (GMT-03:00) America/Argentina/Rio_Gallegos
    [America/Argentina/Catamarca] => (GMT-03:00) America/Argentina/Catamarca
    [America/Maceio] => (GMT-03:00) America/Maceio
    [America/Argentina/San_Juan] => (GMT-03:00) America/Argentina/San_Juan
    [America/Argentina/Salta] => (GMT-03:00) America/Argentina/Salta
    [America/Argentina/Mendoza] => (GMT-03:00) America/Argentina/Mendoza
    [America/Argentina/Cordoba] => (GMT-03:00) America/Argentina/Cordoba
    [America/Argentina/Jujuy] => (GMT-03:00) America/Argentina/Jujuy
    [Atlantic/South_Georgia] => (GMT-02:00) Atlantic/South_Georgia
    [America/Noronha] => (GMT-02:00) America/Noronha
    [America/Sao_Paulo] => (GMT-02:00) America/Sao_Paulo
    [Atlantic/Cape_Verde] => (GMT-01:00) Atlantic/Cape_Verde
    [Atlantic/Azores] => (GMT-01:00) Atlantic/Azores
    [America/Scoresbysund] => (GMT-01:00) America/Scoresbysund
    [Europe/Lisbon] => (GMT+00:00) Europe/Lisbon
    [Europe/London] => (GMT+00:00) Europe/London
    [Europe/Jersey] => (GMT+00:00) Europe/Jersey
    [Europe/Isle_of_Man] => (GMT+00:00) Europe/Isle_of_Man
    [Atlantic/Faroe] => (GMT+00:00) Atlantic/Faroe
    [Europe/Guernsey] => (GMT+00:00) Europe/Guernsey
    [Europe/Dublin] => (GMT+00:00) Europe/Dublin
    [Atlantic/St_Helena] => (GMT+00:00) Atlantic/St_Helena
    [Atlantic/Reykjavik] => (GMT+00:00) Atlantic/Reykjavik
    [Atlantic/Madeira] => (GMT+00:00) Atlantic/Madeira
    [Atlantic/Canary] => (GMT+00:00) Atlantic/Canary
    [Africa/Accra] => (GMT+00:00) Africa/Accra
    [Antarctica/Troll] => (GMT+00:00) Antarctica/Troll
    [Africa/Abidjan] => (GMT+00:00) Africa/Abidjan
    [UTC] => (GMT+00:00) UTC
    [America/Danmarkshavn] => (GMT+00:00) America/Danmarkshavn
    [Africa/Monrovia] => (GMT+00:00) Africa/Monrovia
    [Africa/Dakar] => (GMT+00:00) Africa/Dakar
    [Africa/Conakry] => (GMT+00:00) Africa/Conakry
    [Africa/Casablanca] => (GMT+00:00) Africa/Casablanca
    [Africa/Lome] => (GMT+00:00) Africa/Lome
    [Africa/Freetown] => (GMT+00:00) Africa/Freetown
    [Africa/El_Aaiun] => (GMT+00:00) Africa/El_Aaiun
    [Africa/Bissau] => (GMT+00:00) Africa/Bissau
    [Africa/Nouakchott] => (GMT+00:00) Africa/Nouakchott
    [Africa/Banjul] => (GMT+00:00) Africa/Banjul
    [Africa/Ouagadougou] => (GMT+00:00) Africa/Ouagadougou
    [Africa/Bamako] => (GMT+00:00) Africa/Bamako
    [Europe/Gibraltar] => (GMT+01:00) Europe/Gibraltar
    [Africa/Bangui] => (GMT+01:00) Africa/Bangui
    [Europe/Ljubljana] => (GMT+01:00) Europe/Ljubljana
    [Africa/Ceuta] => (GMT+01:00) Africa/Ceuta
    [Africa/Algiers] => (GMT+01:00) Africa/Algiers
    [Europe/Busingen] => (GMT+01:00) Europe/Busingen
    [Europe/Copenhagen] => (GMT+01:00) Europe/Copenhagen
    [Europe/Madrid] => (GMT+01:00) Europe/Madrid
    [Europe/Budapest] => (GMT+01:00) Europe/Budapest
    [Europe/Brussels] => (GMT+01:00) Europe/Brussels
    [Europe/Bratislava] => (GMT+01:00) Europe/Bratislava
    [Europe/Berlin] => (GMT+01:00) Europe/Berlin
    [Europe/Belgrade] => (GMT+01:00) Europe/Belgrade
    [Europe/Andorra] => (GMT+01:00) Europe/Andorra
    [Europe/Amsterdam] => (GMT+01:00) Europe/Amsterdam
    [Europe/Luxembourg] => (GMT+01:00) Europe/Luxembourg
    [Europe/Monaco] => (GMT+01:00) Europe/Monaco
    [Europe/Malta] => (GMT+01:00) Europe/Malta
    [Europe/Tirane] => (GMT+01:00) Europe/Tirane
    [Europe/Zurich] => (GMT+01:00) Europe/Zurich
    [Europe/Zagreb] => (GMT+01:00) Europe/Zagreb
    [Europe/Warsaw] => (GMT+01:00) Europe/Warsaw
    [Europe/Vienna] => (GMT+01:00) Europe/Vienna
    [Europe/Vatican] => (GMT+01:00) Europe/Vatican
    [Europe/Vaduz] => (GMT+01:00) Europe/Vaduz
    [Europe/Stockholm] => (GMT+01:00) Europe/Stockholm
    [Africa/Brazzaville] => (GMT+01:00) Africa/Brazzaville
    [Europe/Skopje] => (GMT+01:00) Europe/Skopje
    [Europe/Sarajevo] => (GMT+01:00) Europe/Sarajevo
    [Europe/San_Marino] => (GMT+01:00) Europe/San_Marino
    [Europe/Rome] => (GMT+01:00) Europe/Rome
    [Europe/Prague] => (GMT+01:00) Europe/Prague
    [Europe/Paris] => (GMT+01:00) Europe/Paris
    [Europe/Oslo] => (GMT+01:00) Europe/Oslo
    [Europe/Podgorica] => (GMT+01:00) Europe/Podgorica
    [Africa/Douala] => (GMT+01:00) Africa/Douala
    [Arctic/Longyearbyen] => (GMT+01:00) Arctic/Longyearbyen
    [Africa/Malabo] => (GMT+01:00) Africa/Malabo
    [Africa/Kinshasa] => (GMT+01:00) Africa/Kinshasa
    [Africa/Libreville] => (GMT+01:00) Africa/Libreville
    [Africa/Ndjamena] => (GMT+01:00) Africa/Ndjamena
    [Africa/Lagos] => (GMT+01:00) Africa/Lagos
    [Africa/Niamey] => (GMT+01:00) Africa/Niamey
    [Africa/Porto-Novo] => (GMT+01:00) Africa/Porto-Novo
    [Africa/Sao_Tome] => (GMT+01:00) Africa/Sao_Tome
    [Africa/Luanda] => (GMT+01:00) Africa/Luanda
    [Africa/Tunis] => (GMT+01:00) Africa/Tunis
    [Europe/Uzhgorod] => (GMT+02:00) Europe/Uzhgorod
    [Africa/Harare] => (GMT+02:00) Africa/Harare
    [Europe/Mariehamn] => (GMT+02:00) Europe/Mariehamn
    [Africa/Lubumbashi] => (GMT+02:00) Africa/Lubumbashi
    [Asia/Nicosia] => (GMT+02:00) Asia/Nicosia
    [Africa/Windhoek] => (GMT+02:00) Africa/Windhoek
    [Europe/Tallinn] => (GMT+02:00) Europe/Tallinn
    [Europe/Zaporozhye] => (GMT+02:00) Europe/Zaporozhye
    [Africa/Gaborone] => (GMT+02:00) Africa/Gaborone
    [Africa/Mbabane] => (GMT+02:00) Africa/Mbabane
    [Africa/Khartoum] => (GMT+02:00) Africa/Khartoum
    [Africa/Johannesburg] => (GMT+02:00) Africa/Johannesburg
    [Europe/Vilnius] => (GMT+02:00) Europe/Vilnius
    [Africa/Maseru] => (GMT+02:00) Africa/Maseru
    [Africa/Lusaka] => (GMT+02:00) Africa/Lusaka
    [Europe/Riga] => (GMT+02:00) Europe/Riga
    [Africa/Kigali] => (GMT+02:00) Africa/Kigali
    [Europe/Helsinki] => (GMT+02:00) Europe/Helsinki
    [Africa/Maputo] => (GMT+02:00) Africa/Maputo
    [Europe/Chisinau] => (GMT+02:00) Europe/Chisinau
    [Europe/Sofia] => (GMT+02:00) Europe/Sofia
    [Asia/Beirut] => (GMT+02:00) Asia/Beirut
    [Africa/Blantyre] => (GMT+02:00) Africa/Blantyre
    [Asia/Jerusalem] => (GMT+02:00) Asia/Jerusalem
    [Asia/Gaza] => (GMT+02:00) Asia/Gaza
    [Asia/Amman] => (GMT+02:00) Asia/Amman
    [Asia/Famagusta] => (GMT+02:00) Asia/Famagusta
    [Europe/Athens] => (GMT+02:00) Europe/Athens
    [Africa/Bujumbura] => (GMT+02:00) Africa/Bujumbura
    [Asia/Hebron] => (GMT+02:00) Asia/Hebron
    [Europe/Kaliningrad] => (GMT+02:00) Europe/Kaliningrad
    [Africa/Cairo] => (GMT+02:00) Africa/Cairo
    [Europe/Kiev] => (GMT+02:00) Europe/Kiev
    [Europe/Bucharest] => (GMT+02:00) Europe/Bucharest
    [Asia/Damascus] => (GMT+02:00) Asia/Damascus
    [Africa/Tripoli] => (GMT+02:00) Africa/Tripoli
    [Asia/Baghdad] => (GMT+03:00) Asia/Baghdad
    [Africa/Djibouti] => (GMT+03:00) Africa/Djibouti
    [Asia/Aden] => (GMT+03:00) Asia/Aden
    [Asia/Bahrain] => (GMT+03:00) Asia/Bahrain
    [Europe/Istanbul] => (GMT+03:00) Europe/Istanbul
    [Africa/Juba] => (GMT+03:00) Africa/Juba
    [Europe/Kirov] => (GMT+03:00) Europe/Kirov
    [Europe/Moscow] => (GMT+03:00) Europe/Moscow
    [Antarctica/Syowa] => (GMT+03:00) Antarctica/Syowa
    [Europe/Minsk] => (GMT+03:00) Europe/Minsk
    [Africa/Kampala] => (GMT+03:00) Africa/Kampala
    [Africa/Dar_es_Salaam] => (GMT+03:00) Africa/Dar_es_Salaam
    [Europe/Simferopol] => (GMT+03:00) Europe/Simferopol
    [Asia/Riyadh] => (GMT+03:00) Asia/Riyadh
    [Indian/Antananarivo] => (GMT+03:00) Indian/Antananarivo
    [Asia/Kuwait] => (GMT+03:00) Asia/Kuwait
    [Africa/Nairobi] => (GMT+03:00) Africa/Nairobi
    [Indian/Mayotte] => (GMT+03:00) Indian/Mayotte
    [Africa/Mogadishu] => (GMT+03:00) Africa/Mogadishu
    [Asia/Qatar] => (GMT+03:00) Asia/Qatar
    [Europe/Volgograd] => (GMT+03:00) Europe/Volgograd
    [Africa/Asmara] => (GMT+03:00) Africa/Asmara
    [Africa/Addis_Ababa] => (GMT+03:00) Africa/Addis_Ababa
    [Indian/Comoro] => (GMT+03:00) Indian/Comoro
    [Asia/Tehran] => (GMT+03:30) Asia/Tehran
    [Europe/Saratov] => (GMT+04:00) Europe/Saratov
    [Indian/Reunion] => (GMT+04:00) Indian/Reunion
    [Europe/Astrakhan] => (GMT+04:00) Europe/Astrakhan
    [Asia/Baku] => (GMT+04:00) Asia/Baku
    [Asia/Dubai] => (GMT+04:00) Asia/Dubai
    [Indian/Mauritius] => (GMT+04:00) Indian/Mauritius
    [Indian/Mahe] => (GMT+04:00) Indian/Mahe
    [Asia/Tbilisi] => (GMT+04:00) Asia/Tbilisi
    [Asia/Yerevan] => (GMT+04:00) Asia/Yerevan
    [Asia/Muscat] => (GMT+04:00) Asia/Muscat
    [Europe/Samara] => (GMT+04:00) Europe/Samara
    [Europe/Ulyanovsk] => (GMT+04:00) Europe/Ulyanovsk
    [Asia/Kabul] => (GMT+04:30) Asia/Kabul
    [Antarctica/Mawson] => (GMT+05:00) Antarctica/Mawson
    [Asia/Samarkand] => (GMT+05:00) Asia/Samarkand
    [Asia/Aqtobe] => (GMT+05:00) Asia/Aqtobe
    [Indian/Maldives] => (GMT+05:00) Indian/Maldives
    [Asia/Ashgabat] => (GMT+05:00) Asia/Ashgabat
    [Asia/Atyrau] => (GMT+05:00) Asia/Atyrau
    [Asia/Dushanbe] => (GMT+05:00) Asia/Dushanbe
    [Asia/Yekaterinburg] => (GMT+05:00) Asia/Yekaterinburg
    [Asia/Oral] => (GMT+05:00) Asia/Oral
    [Asia/Aqtau] => (GMT+05:00) Asia/Aqtau
    [Asia/Karachi] => (GMT+05:00) Asia/Karachi
    [Asia/Tashkent] => (GMT+05:00) Asia/Tashkent
    [Indian/Kerguelen] => (GMT+05:00) Indian/Kerguelen
    [Asia/Colombo] => (GMT+05:30) Asia/Colombo
    [Asia/Kolkata] => (GMT+05:30) Asia/Kolkata
    [Asia/Kathmandu] => (GMT+05:45) Asia/Kathmandu
    [Antarctica/Vostok] => (GMT+06:00) Antarctica/Vostok
    [Indian/Chagos] => (GMT+06:00) Indian/Chagos
    [Asia/Almaty] => (GMT+06:00) Asia/Almaty
    [Asia/Omsk] => (GMT+06:00) Asia/Omsk
    [Asia/Dhaka] => (GMT+06:00) Asia/Dhaka
    [Asia/Bishkek] => (GMT+06:00) Asia/Bishkek
    [Asia/Urumqi] => (GMT+06:00) Asia/Urumqi
    [Asia/Thimphu] => (GMT+06:00) Asia/Thimphu
    [Asia/Qyzylorda] => (GMT+06:00) Asia/Qyzylorda
    [Indian/Cocos] => (GMT+06:30) Indian/Cocos
    [Asia/Yangon] => (GMT+06:30) Asia/Yangon
    [Asia/Novokuznetsk] => (GMT+07:00) Asia/Novokuznetsk
    [Asia/Barnaul] => (GMT+07:00) Asia/Barnaul
    [Antarctica/Davis] => (GMT+07:00) Antarctica/Davis
    [Asia/Novosibirsk] => (GMT+07:00) Asia/Novosibirsk
    [Asia/Krasnoyarsk] => (GMT+07:00) Asia/Krasnoyarsk
    [Asia/Phnom_Penh] => (GMT+07:00) Asia/Phnom_Penh
    [Asia/Pontianak] => (GMT+07:00) Asia/Pontianak
    [Asia/Jakarta] => (GMT+07:00) Asia/Jakarta
    [Asia/Hovd] => (GMT+07:00) Asia/Hovd
    [Asia/Tomsk] => (GMT+07:00) Asia/Tomsk
    [Asia/Ho_Chi_Minh] => (GMT+07:00) Asia/Ho_Chi_Minh
    [Asia/Vientiane] => (GMT+07:00) Asia/Vientiane
    [Indian/Christmas] => (GMT+07:00) Indian/Christmas
    [Asia/Bangkok] => (GMT+07:00) Asia/Bangkok
    [Asia/Choibalsan] => (GMT+08:00) Asia/Choibalsan
    [Asia/Taipei] => (GMT+08:00) Asia/Taipei
    [Asia/Makassar] => (GMT+08:00) Asia/Makassar
    [Asia/Macau] => (GMT+08:00) Asia/Macau
    [Asia/Kuching] => (GMT+08:00) Asia/Kuching
    [Asia/Kuala_Lumpur] => (GMT+08:00) Asia/Kuala_Lumpur
    [Asia/Shanghai] => (GMT+08:00) Asia/Shanghai
    [Asia/Singapore] => (GMT+08:00) Asia/Singapore
    [Asia/Brunei] => (GMT+08:00) Asia/Brunei
    [Asia/Irkutsk] => (GMT+08:00) Asia/Irkutsk
    [Asia/Ulaanbaatar] => (GMT+08:00) Asia/Ulaanbaatar
    [Australia/Perth] => (GMT+08:00) Australia/Perth
    [Asia/Hong_Kong] => (GMT+08:00) Asia/Hong_Kong
    [Antarctica/Casey] => (GMT+08:00) Antarctica/Casey
    [Asia/Manila] => (GMT+08:00) Asia/Manila
    [Australia/Eucla] => (GMT+08:45) Australia/Eucla
    [Asia/Jayapura] => (GMT+09:00) Asia/Jayapura
    [Asia/Khandyga] => (GMT+09:00) Asia/Khandyga
    [Pacific/Palau] => (GMT+09:00) Pacific/Palau
    [Asia/Dili] => (GMT+09:00) Asia/Dili
    [Asia/Yakutsk] => (GMT+09:00) Asia/Yakutsk
    [Asia/Tokyo] => (GMT+09:00) Asia/Tokyo
    [Asia/Seoul] => (GMT+09:00) Asia/Seoul
    [Asia/Chita] => (GMT+09:00) Asia/Chita
    [Asia/Pyongyang] => (GMT+09:00) Asia/Pyongyang
    [Australia/Darwin] => (GMT+09:30) Australia/Darwin
    [Asia/Ust-Nera] => (GMT+10:00) Asia/Ust-Nera
    [Pacific/Chuuk] => (GMT+10:00) Pacific/Chuuk
    [Antarctica/DumontDUrville] => (GMT+10:00) Antarctica/DumontDUrville
    [Pacific/Guam] => (GMT+10:00) Pacific/Guam
    [Pacific/Port_Moresby] => (GMT+10:00) Pacific/Port_Moresby
    [Asia/Vladivostok] => (GMT+10:00) Asia/Vladivostok
    [Australia/Brisbane] => (GMT+10:00) Australia/Brisbane
    [Australia/Lindeman] => (GMT+10:00) Australia/Lindeman
    [Pacific/Saipan] => (GMT+10:00) Pacific/Saipan
    [Australia/Adelaide] => (GMT+10:30) Australia/Adelaide
    [Australia/Broken_Hill] => (GMT+10:30) Australia/Broken_Hill
    [Australia/Sydney] => (GMT+11:00) Australia/Sydney
    [Antarctica/Macquarie] => (GMT+11:00) Antarctica/Macquarie
    [Pacific/Noumea] => (GMT+11:00) Pacific/Noumea
    [Pacific/Norfolk] => (GMT+11:00) Pacific/Norfolk
    [Australia/Melbourne] => (GMT+11:00) Australia/Melbourne
    [Pacific/Kosrae] => (GMT+11:00) Pacific/Kosrae
    [Pacific/Pohnpei] => (GMT+11:00) Pacific/Pohnpei
    [Australia/Currie] => (GMT+11:00) Australia/Currie
    [Pacific/Guadalcanal] => (GMT+11:00) Pacific/Guadalcanal
    [Pacific/Efate] => (GMT+11:00) Pacific/Efate
    [Australia/Hobart] => (GMT+11:00) Australia/Hobart
    [Asia/Magadan] => (GMT+11:00) Asia/Magadan
    [Asia/Sakhalin] => (GMT+11:00) Asia/Sakhalin
    [Pacific/Bougainville] => (GMT+11:00) Pacific/Bougainville
    [Australia/Lord_Howe] => (GMT+11:00) Australia/Lord_Howe
    [Asia/Srednekolymsk] => (GMT+11:00) Asia/Srednekolymsk
    [Pacific/Fiji] => (GMT+12:00) Pacific/Fiji
    [Pacific/Wake] => (GMT+12:00) Pacific/Wake
    [Pacific/Nauru] => (GMT+12:00) Pacific/Nauru
    [Pacific/Majuro] => (GMT+12:00) Pacific/Majuro
    [Asia/Kamchatka] => (GMT+12:00) Asia/Kamchatka
    [Pacific/Kwajalein] => (GMT+12:00) Pacific/Kwajalein
    [Pacific/Funafuti] => (GMT+12:00) Pacific/Funafuti
    [Pacific/Wallis] => (GMT+12:00) Pacific/Wallis
    [Asia/Anadyr] => (GMT+12:00) Asia/Anadyr
    [Pacific/Tarawa] => (GMT+12:00) Pacific/Tarawa
    [Pacific/Fakaofo] => (GMT+13:00) Pacific/Fakaofo
    [Pacific/Enderbury] => (GMT+13:00) Pacific/Enderbury
    [Pacific/Auckland] => (GMT+13:00) Pacific/Auckland
    [Antarctica/McMurdo] => (GMT+13:00) Antarctica/McMurdo
    [Pacific/Tongatapu] => (GMT+13:00) Pacific/Tongatapu
    [Pacific/Chatham] => (GMT+13:45) Pacific/Chatham
    [Pacific/Kiritimati] => (GMT+14:00) Pacific/Kiritimati
    [Pacific/Apia] => (GMT+14:00) Pacific/Apia
)

the first option would allow you to take the value from $_POST[ whateveryoucalltheselect ] and add it to UTC. or even store that value and then always call UTC + userTZsetting whenever you need it later. seems easiest to me. the last option would be much more valuable if timezones changed frequently.

None of them. Instead prepare an array in PHP with those timezones. Like

$arr[0] = "(GMT+02:00) Harare, Pretoria";
$arr[1] = "(GMT+03:00) Jerusalem";

or

$arr[0] = array("America/Campo_Grande", "(GMT+02:00) Harare, Pretoria");
$arr[1] = array("America/Israel", "(GMT+03:00) Jerusalem");

and so on. Then generate form based on this array:

foreach ($arr as $k => $v)
   $str .= "<option value=$k>$v[1]</option>";

And then you may easily switch with different formats with just code modification in above line. Also validation will be much easier and don t require regular expressions. Just compare value sent by POST or GET with an array. Now it s easy to set $arr[$value_sent_by_form][0] holds PHP compatible value while $arr[$value_sent_by_form][1] user friendly value.

See this example also

<?php
     function get_timezones() 
     {
        $o = array();
        $t_zones = timezone_identifiers_list();
        foreach($t_zones as $a)
        {
            $t =   ;

            try
            {
                //this throws exception for  US/Pacific-New 
                $zone = new DateTimeZone($a);

                $seconds = $zone->getOffset( new DateTime("now" , $zone) );
                $hours = sprintf( "%+02d" , intval($seconds/3600));
                $minutes = sprintf( "%02d" , ($seconds%3600)/60 );

                $t = $a ."  [ $hours:$minutes ]" ;

                $o[$a] = $t;
            }

            //exceptions must be catched, else a blank page
            catch(Exception $e)
            {
                //die("Exception : " . $e->getMessage() .  <br /> );
                //what to do in catch ? , nothing just relax
            }
        }

        ksort($o);

        return $o;
    } 

    $o = get_timezones();
    ?>

    <html>
    <body>
    <select name="time_zone">
    <?php
        foreach($o as $tz => $label)
        {
            echo "<option value="$tz">$label</option>";
        }
    ?>
    </select>
    </body>
    </html>

After trying all solutions presented here and not being satisfied, I have found a script which is matching my needs and it is more user friendly. For the record, I will save it as a possible solution. I love the copy/paste solutions :)

Script returns a select with whatever timezone you want preselected.

Source: https://e-tel.eu/2011/07/13/create-a-time-zone-drop-down-list-ddl-in-php/

<?php
/**
 * returns a HTML formated TimeZone select
 *
 * PHP 5 >= 5.2.0
 * 
 * @param $selectedTimeZone string The timezone marked as "selected"
 * @return string
 */
function displayTimeZoneSelect($selectedTimeZone =  America/New_York ){
    $countryCodes = getCountryCodes();
    $return = null;
    foreach ($countryCodes as $country => $countryCode) {
        $timezone_identifiers = DateTimeZone::listIdentifiers(DateTimeZone::PER_COUNTRY,$countryCode);
        foreach( $timezone_identifiers as $value ){
            /* getTimeZoneOffset returns minutes and we need to display hours */
            $offset = getTimeZoneOffset($value)/60;
            /* for the GMT+1 GMT-1 display */
            $offset = ( substr($offset,0,1) == "-" ? " (GMT" : " (GMT+" ) . $offset . ")";
            /* America/New_York -> America/New York */
            $displayValue = (str_replace( _ ,   ,$value));
            /* Find the city */
            $ex = explode("/",$displayValue);
            $city = ( ($ex[2]) ? $ex[2] : $ex[1] );
            /* For the special names */
            $displayValue = htmlentities($country." - ".$city.$offset); 
            /* handle the $selectedTimeZone in the select form */
            $selected = ( ($value == $selectedTimeZone) ?   selected="selected"  : null );
            $return .=  <option value="  . $value .  "  . $selected .  > 
                . $displayValue
                .  </option>  . PHP_EOL;
        }
    }

    return $return;
}

/**
 * ISO 3166 code list
 *
 * @return array The country codes in  COUNTRY  =>  CODE  format
 * @link http://www.iso.org/iso/iso_3166_code_lists ISO Website
 */
function getCountryCodes(){
$return = array(
"AFGHANISTAN"=>"AF",
"ALAND ISLANDS"=>"AX",
"ALBANIA"=>"AL",
"ALGERIA"=>"DZ",
"AMERICAN SAMOA"=>"AS",
"ANDORRA"=>"AD",
"ANGOLA"=>"AO",
"ANGUILLA"=>"AI",
"ANTARCTICA"=>"AQ",
"ANTIGUA AND BARBUDA"=>"AG",
"ARGENTINA"=>"AR",
"ARMENIA"=>"AM",
"ARUBA"=>"AW",
"AUSTRALIA"=>"AU",
"AUSTRIA"=>"AT",
"AZERBAIJAN"=>"AZ",
"BAHAMAS"=>"BS",
"BAHRAIN"=>"BH",
"BANGLADESH"=>"BD",
"BARBADOS"=>"BB",
"BELARUS"=>"BY",
"BELGIUM"=>"BE",
"BELIZE"=>"BZ",
"BENIN"=>"BJ",
"BERMUDA"=>"BM",
"BHUTAN"=>"BT",
"BOLIVIA, PLURINATIONAL STATE OF"=>"BO",
"BONAIRE, SINT EUSTATIUS AND SABA"=>"BQ",
"BOSNIA AND HERZEGOVINA"=>"BA",
"BOTSWANA"=>"BW",
"BOUVET ISLAND"=>"BV",
"BRAZIL"=>"BR",
"BRITISH INDIAN OCEAN TERRITORY"=>"IO",
"BRUNEI DARUSSALAM"=>"BN",
"BULGARIA"=>"BG",
"BURKINA FASO"=>"BF",
"BURUNDI"=>"BI",
"CAMBODIA"=>"KH",
"CAMEROON"=>"CM",
"CANADA"=>"CA",
"CAPE VERDE"=>"CV",
"CAYMAN ISLANDS"=>"KY",
"CENTRAL AFRICAN REPUBLIC"=>"CF",
"CHAD"=>"TD",
"CHILE"=>"CL",
"CHINA"=>"CN",
"CHRISTMAS ISLAND"=>"CX",
"COCOS (KEELING) ISLANDS"=>"CC",
"COLOMBIA"=>"CO",
"COMOROS"=>"KM",
"CONGO"=>"CG",
"CONGO, THE DEMOCRATIC REPUBLIC OF THE"=>"CD",
"COOK ISLANDS"=>"CK",
"COSTA RICA"=>"CR",
"CÔTE D IVOIRE"=>"CI",
"CROATIA"=>"HR",
"CUBA"=>"CU",
"CURAÇAO"=>"CW",
"CYPRUS"=>"CY",
"CZECH REPUBLIC"=>"CZ",
"DENMARK"=>"DK",
"DJIBOUTI"=>"DJ",
"DOMINICA"=>"DM",
"DOMINICAN REPUBLIC"=>"DO",
"ECUADOR"=>"EC",
"EGYPT"=>"EG",
"EL SALVADOR"=>"SV",
"EQUATORIAL GUINEA"=>"GQ",
"ERITREA"=>"ER",
"ESTONIA"=>"EE",
"ETHIOPIA"=>"ET",
"FALKLAND ISLANDS (MALVINAS)"=>"FK",
"FAROE ISLANDS"=>"FO",
"FIJI"=>"FJ",
"FINLAND"=>"FI",
"FRANCE"=>"FR",
"FRENCH GUIANA"=>"GF",
"FRENCH POLYNESIA"=>"PF",
"FRENCH SOUTHERN TERRITORIES"=>"TF",
"GABON"=>"GA",
"GAMBIA"=>"GM",
"GEORGIA"=>"GE",
"GERMANY"=>"DE",
"GHANA"=>"GH",
"GIBRALTAR"=>"GI",
"GREECE"=>"GR",
"GREENLAND"=>"GL",
"GRENADA"=>"GD",
"GUADELOUPE"=>"GP",
"GUAM"=>"GU",
"GUATEMALA"=>"GT",
"GUERNSEY"=>"GG",
"GUINEA"=>"GN",
"GUINEA-BISSAU"=>"GW",
"GUYANA"=>"GY",
"HAITI"=>"HT",
"HEARD ISLAND AND MCDONALD ISLANDS"=>"HM",
"HOLY SEE (VATICAN CITY STATE)"=>"VA",
"HONDURAS"=>"HN",
"HONG KONG"=>"HK",
"HUNGARY"=>"HU",
"ICELAND"=>"IS",
"INDIA"=>"IN",
"INDONESIA"=>"ID",
"IRAN, ISLAMIC REPUBLIC OF"=>"IR",
"IRAQ"=>"IQ",
"IRELAND"=>"IE",
"ISLE OF MAN"=>"IM",
"ISRAEL"=>"IL",
"ITALY"=>"IT",
"JAMAICA"=>"JM",
"JAPAN"=>"JP",
"JERSEY"=>"JE",
"JORDAN"=>"JO",
"KAZAKHSTAN"=>"KZ",
"KENYA"=>"KE",
"KIRIBATI"=>"KI",
"KOREA, DEMOCRATIC PEOPLE S REPUBLIC OF"=>"KP",
"KOREA, REPUBLIC OF"=>"KR",
"KUWAIT"=>"KW",
"KYRGYZSTAN"=>"KG",
"LAO PEOPLE S DEMOCRATIC REPUBLIC"=>"LA",
"LATVIA"=>"LV",
"LEBANON"=>"LB",
"LESOTHO"=>"LS",
"LIBERIA"=>"LR",
"LIBYAN ARAB JAMAHIRIYA"=>"LY",
"LIECHTENSTEIN"=>"LI",
"LITHUANIA"=>"LT",
"LUXEMBOURG"=>"LU",
"MACAO"=>"MO",
"MACEDONIA, THE FORMER YUGOSLAV REPUBLIC OF"=>"MK",
"MADAGASCAR"=>"MG",
"MALAWI"=>"MW",
"MALAYSIA"=>"MY",
"MALDIVES"=>"MV",
"MALI"=>"ML",
"MALTA"=>"MT",
"MARSHALL ISLANDS"=>"MH",
"MARTINIQUE"=>"MQ",
"MAURITANIA"=>"MR",
"MAURITIUS"=>"MU",
"MAYOTTE"=>"YT",
"MEXICO"=>"MX",
"MICRONESIA, FEDERATED STATES OF"=>"FM",
"MOLDOVA, REPUBLIC OF"=>"MD",
"MONACO"=>"MC",
"MONGOLIA"=>"MN",
"MONTENEGRO"=>"ME",
"MONTSERRAT"=>"MS",
"MOROCCO"=>"MA",
"MOZAMBIQUE"=>"MZ",
"MYANMAR"=>"MM",
"NAMIBIA"=>"NA",
"NAURU"=>"NR",
"NEPAL"=>"NP",
"NETHERLANDS"=>"NL",
"NEW CALEDONIA"=>"NC",
"NEW ZEALAND"=>"NZ",
"NICARAGUA"=>"NI",
"NIGER"=>"NE",
"NIGERIA"=>"NG",
"NIUE"=>"NU",
"NORFOLK ISLAND"=>"NF",
"NORTHERN MARIANA ISLANDS"=>"MP",
"NORWAY"=>"NO",
"OMAN"=>"OM",
"PAKISTAN"=>"PK",
"PALAU"=>"PW",
"PALESTINIAN TERRITORY, OCCUPIED"=>"PS",
"PANAMA"=>"PA",
"PAPUA NEW GUINEA"=>"PG",
"PARAGUAY"=>"PY",
"PERU"=>"PE",
"PHILIPPINES"=>"PH",
"PITCAIRN"=>"PN",
"POLAND"=>"PL",
"PORTUGAL"=>"PT",
"PUERTO RICO"=>"PR",
"QATAR"=>"QA",
"RÉUNION"=>"RE",
"ROMANIA"=>"RO",
"RUSSIAN FEDERATION"=>"RU",
"RWANDA"=>"RW",
"SAINT BARTHÉLEMY"=>"BL",
"SAINT HELENA, ASCENSION AND TRISTAN DA CUNHA"=>"SH",
"SAINT KITTS AND NEVIS"=>"KN",
"SAINT LUCIA"=>"LC",
"SAINT MARTIN (FRENCH PART)"=>"MF",
"SAINT PIERRE AND MIQUELON"=>"PM",
"SAINT VINCENT AND THE GRENADINES"=>"VC",
"SAMOA"=>"WS",
"SAN MARINO"=>"SM",
"SAO TOME AND PRINCIPE"=>"ST",
"SAUDI ARABIA"=>"SA",
"SENEGAL"=>"SN",
"SERBIA"=>"RS",
"SEYCHELLES"=>"SC",
"SIERRA LEONE"=>"SL",
"SINGAPORE"=>"SG",
"SINT MAARTEN (DUTCH PART)"=>"SX",
"SLOVAKIA"=>"SK",
"SLOVENIA"=>"SI",
"SOLOMON ISLANDS"=>"SB",
"SOMALIA"=>"SO",
"SOUTH AFRICA"=>"ZA",
"SOUTH GEORGIA AND THE SOUTH SANDWICH ISLANDS"=>"GS",
"SPAIN"=>"ES",
"SRI LANKA"=>"LK",
"SUDAN"=>"SD",
"SURINAME"=>"SR",
"SVALBARD AND JAN MAYEN"=>"SJ",
"SWAZILAND"=>"SZ",
"SWEDEN"=>"SE",
"SWITZERLAND"=>"CH",
"SYRIAN ARAB REPUBLIC"=>"SY",
"TAIWAN, PROVINCE OF CHINA"=>"TW",
"TAJIKISTAN"=>"TJ",
"TANZANIA, UNITED REPUBLIC OF"=>"TZ",
"THAILAND"=>"TH",
"TIMOR-LESTE"=>"TL",
"TOGO"=>"TG",
"TOKELAU"=>"TK",
"TONGA"=>"TO",
"TRINIDAD AND TOBAGO"=>"TT",
"TUNISIA"=>"TN",
"TURKEY"=>"TR",
"TURKMENISTAN"=>"TM",
"TURKS AND CAICOS ISLANDS"=>"TC",
"TUVALU"=>"TV",
"UGANDA"=>"UG",
"UKRAINE"=>"UA",
"UNITED ARAB EMIRATES"=>"AE",
"UNITED KINGDOM"=>"GB",
"UNITED STATES"=>"US",
"UNITED STATES MINOR OUTLYING ISLANDS"=>"UM",
"URUGUAY"=>"UY",
"UZBEKISTAN"=>"UZ",
"VANUATU"=>"VU",
"VENEZUELA, BOLIVARIAN REPUBLIC OF"=>"VE",
"VIET NAM"=>"VN",
"VIRGIN ISLANDS, BRITISH"=>"VG",
"VIRGIN ISLANDS, U.S."=>"VI",
"WALLIS AND FUTUNA"=>"WF",
"WESTERN SAHARA"=>"EH",
"YEMEN"=>"YE",
"ZAMBIA"=>"ZM",
"ZIMBABWE"=>"ZW");
return $return;
}

/**
 * Calculates the offset from UTC for a given timezone
 *
 * @return integer
 */
function getTimeZoneOffset($timeZone) {
    $dateTimeZoneUTC = new DateTimeZone("UTC");
    $dateTimeZoneCurrent = new DateTimeZone($timeZone);

    $dateTimeUTC = new DateTime("now",$dateTimeZoneUTC);
    $dateTimeCurrent = new DateTime("now",$dateTimeZoneCurrent);

    $offset = (($dateTimeZoneCurrent->getOffset($dateTimeUTC))/60);
    return $offset;
}
?>


    <label for="timeZone">Timezone<br />
        <select id="timeZone" name="timeZone">
            <?php echo displayTimeZoneSelect("America/Toronto");?>
        </select>
    </label>

Here s a class I put together, mixing what I thought was the best of all suggestions here, and with Carbon as a dependency:

namespace AppSupport;

use CarbonCarbon;
use DateTimeZone;

class Timezone
{
    protected static $timezones;

    public static function all(): array
    {
        if (static::$timezones) {
            return static::$timezones;
        }

        $offsets   = [];
        $timezones = [];

        foreach (DateTimeZone::listIdentifiers() as $timezone) {

            $offsets[]            = $offset = Carbon::now()->timezone($timezone)->offset;
            $timezones[$timezone] = static::formatTimezoneDisplay($timezone, $offset);

            array_multisort($offsets, $timezones);

        }

        return static::$timezones = $timezones;
    }

    protected static function formatTimezoneDisplay(string $timezone, string $offset): string
    {
        return static::formatOffset($offset) .   (  . static::formatTimezone($timezone) .  ) ;
    }

    protected static function formatOffset(string $offset): string
    {
        if (!$offset) {
            return  UTC±00:00 ;
        }

        $hours   = intval($offset / 3600);
        $minutes = abs(intval($offset % 3600 / 60));

        return  UTC  . sprintf( %+03d:%02d , $hours, $minutes);
    }

    protected static function formatTimezone(string $timezone): string
    {
        return str_replace([ / ,  _ ,  St  ], [ ,  ,    ,  St.  ], $timezone);
    }
}

You simply Timezone:all(), and that gets you an array in the format of UTC-5:00 (America, New York), so you could easily display a select field on your frontend.

For those using CodeIgniter, there s a built-in Date Helper function called timezone_menu. These:

$this->load->helper( date );
echo timezone_menu( GMT ,  form-control ,  dropdown-name , [ id  =>  ci-timezone ]);

Produce the following output:

<select name="dropdown-name" class="form-control" id="ci-timezone">
  <option value="UM12">(UTC -12:00) Baker/Howland Island</option>
  <option value="UM11">(UTC -11:00) Niue</option>
  <option value="UM10">(UTC -10:00) Hawaii-Aleutian Standard Time, Cook Islands, Tahiti</option>
  <option value="UM95">(UTC -9:30) Marquesas Islands</option>
  <option value="UM9">(UTC -9:00) Alaska Standard Time, Gambier Islands</option>
  <option value="UM8">(UTC -8:00) Pacific Standard Time, Clipperton Island</option>
  <option value="UM7">(UTC -7:00) Mountain Standard Time</option>
  <option value="UM6">(UTC -6:00) Central Standard Time</option>
  <option value="UM5">(UTC -5:00) Eastern Standard Time, Western Caribbean Standard Time</option>
  <option value="UM45">(UTC -4:30) Venezuelan Standard Time</option>
  <option value="UM4">(UTC -4:00) Atlantic Standard Time, Eastern Caribbean Standard Time</option>
  <option value="UM35">(UTC -3:30) Newfoundland Standard Time</option>
  <option value="UM3">(UTC -3:00) Argentina, Brazil, French Guiana, Uruguay</option>
  <option value="UM2">(UTC -2:00) South Georgia/South Sandwich Islands</option>
  <option value="UM1">(UTC -1:00) Azores, Cape Verde Islands</option>
  <option value="UTC" selected="selected">(UTC) Greenwich Mean Time, Western European Time</option>
  <option value="UP1">(UTC +1:00) Central European Time, West Africa Time</option>
  <option value="UP2">(UTC +2:00) Central Africa Time, Eastern European Time, Kaliningrad Time</option>
  <option value="UP3">(UTC +3:00) Moscow Time, East Africa Time, Arabia Standard Time</option>
  <option value="UP35">(UTC +3:30) Iran Standard Time</option>
  <option value="UP4">(UTC +4:00) Azerbaijan Standard Time, Samara Time</option>
  <option value="UP45">(UTC +4:30) Afghanistan</option>
  <option value="UP5">(UTC +5:00) Pakistan Standard Time, Yekaterinburg Time</option>
  <option value="UP55">(UTC +5:30) Indian Standard Time, Sri Lanka Time</option>
  <option value="UP575">(UTC +5:45) Nepal Time</option>
  <option value="UP6">(UTC +6:00) Bangladesh Standard Time, Bhutan Time, Omsk Time</option>
  <option value="UP65">(UTC +6:30) Cocos Islands, Myanmar</option>
  <option value="UP7">(UTC +7:00) Krasnoyarsk Time, Cambodia, Laos, Thailand, Vietnam</option>
  <option value="UP8">(UTC +8:00) Australian Western Standard Time, Beijing Time, Irkutsk Time</option>
  <option value="UP875">(UTC +8:45) Australian Central Western Standard Time</option>
  <option value="UP9">(UTC +9:00) Japan Standard Time, Korea Standard Time, Yakutsk Time</option>
  <option value="UP95">(UTC +9:30) Australian Central Standard Time</option>
  <option value="UP10">(UTC +10:00) Australian Eastern Standard Time, Vladivostok Time</option>
  <option value="UP105">(UTC +10:30) Lord Howe Island</option>
  <option value="UP11">(UTC +11:00) Srednekolymsk Time, Solomon Islands, Vanuatu</option>
  <option value="UP115">(UTC +11:30) Norfolk Island</option>
  <option value="UP12">(UTC +12:00) Fiji, Gilbert Islands, Kamchatka Time, New Zealand Standard Time</option>
  <option value="UP1275">(UTC +12:45) Chatham Islands Standard Time</option>
  <option value="UP13">(UTC +13:00) Samoa Time Zone, Phoenix Islands Time, Tonga</option>
  <option value="UP14">(UTC +14:00) Line Islands</option>
</select>

I did this:

php -r "echo json_encode(array_combine(DateTimeZone::listIdentifiers(DateTimeZone::ALL), DateTimeZone::listIdentifiers(DateTimeZone::ALL)));" > list-of-timezones.json

I would like to leave here this idea:

/*----------TIME ZONE LIST---------*/
function TZList($data_type = false){
    $_all_timezone_identifiers = DateTimeZone::listIdentifiers(DateTimeZone::ALL);
    $TIMEZONE_LIST = array();
    foreach($_all_timezone_identifiers as $k => $v){
        $_tzone_group = explode("/", $_all_timezone_identifiers[$k])[0];

        $_tzone_new = new DateTimeZone($_all_timezone_identifiers[$k]);
        $_tzone_new_date = new DateTime("now", $_tzone_new);

        $tzone_arr = array(
                             timezone  => $_all_timezone_identifiers[$k],
                             timediff  => $_tzone_new_date->format( P ),
                             timezone_offset  => $_tzone_new_date->format( Z )/60, //minutes
                             text  => "(GMT" .$_tzone_new_date->format( P ) .") " .$_all_timezone_identifiers[$k]
                            );

        //BY CONTINENT
        if($data_type === true) $TIMEZONE_LIST[$_tzone_group][] = $tzone_arr; else $TIMEZONE_LIST[] = $tzone_arr;
    }

    //BY TIMEZONE: "America/New_York"
    if(is_string($data_type)){
        $key = array_search($data_type, array_column($TIMEZONE_LIST,  timezone ));
        $TIMEZONE_LIST = $key !== false ? $TIMEZONE_LIST[$key] : null;
    }

    return $TIMEZONE_LIST;
}
/*--------------------------------*/

Thank you.

America Country - Time with Timezones List in Array Format.

$america_timezones_list = array(
         +00:00||America/Danmarkshavn => (+00:00) Danmarkshavn ,
         -01:00||America/Scoresbysund => (-01:00) Scoresbysund ,
         -02:00||America/Miquelon => (-02:00) Miquelon ,
         -02:00||America/Noronha => (-02:00) Noronha ,
         -02:30||America/St_Johns => (-02:30) St_Johns ,
         -03:00||America/Araguaina => (-03:00) Araguaina ,
         -03:00||America/Argentina/Buenos_Aires => (-03:00) Argentina/Buenos_Aires ,
         -03:00||America/Argentina/Catamarca => (-03:00) Argentina/Catamarca ,
         -03:00||America/Argentina/Cordoba => (-03:00) Argentina/Cordoba ,
         -03:00||America/Argentina/Jujuy => (-03:00) Argentina/Jujuy ,
         -03:00||America/Argentina/La_Rioja => (-03:00) Argentina/La_Rioja ,
         -03:00||America/Argentina/Mendoza => (-03:00) Argentina/Mendoza ,
         -03:00||America/Argentina/Rio_Gallegos => (-03:00) Argentina/Rio_Gallegos ,
         -03:00||America/Argentina/Salta => (-03:00) Argentina/Salta ,
         -03:00||America/Argentina/San_Juan => (-03:00) Argentina/San_Juan ,
         -03:00||America/Argentina/San_Luis => (-03:00) Argentina/San_Luis ,
         -03:00||America/Argentina/Tucuman => (-03:00) Argentina/Tucuman ,
         -03:00||America/Argentina/Ushuaia => (-03:00) Argentina/Ushuaia ,
         -03:00||America/Asuncion => (-03:00) Asuncion ,
         -03:00||America/Bahia => (-03:00) Bahia ,
         -03:00||America/Belem => (-03:00) Belem ,
         -03:00||America/Cayenne => (-03:00) Cayenne ,
         -03:00||America/Fortaleza => (-03:00) Fortaleza ,
         -03:00||America/Glace_Bay => (-03:00) Glace_Bay ,
         -03:00||America/Godthab => (-03:00) Godthab ,
         -03:00||America/Goose_Bay => (-03:00) Goose_Bay ,
         -03:00||America/Halifax => (-03:00) Halifax ,
         -03:00||America/Maceio => (-03:00) Maceio ,
         -03:00||America/Moncton => (-03:00) Moncton ,
         -03:00||America/Montevideo => (-03:00) Montevideo ,
         -03:00||America/Paramaribo => (-03:00) Paramaribo ,
         -03:00||America/Punta_Arenas => (-03:00) Punta_Arenas ,
         -03:00||America/Recife => (-03:00) Recife ,
         -03:00||America/Santarem => (-03:00) Santarem ,
         -03:00||America/Santiago => (-03:00) Santiago ,
         -03:00||America/Sao_Paulo => (-03:00) Sao_Paulo ,
         -03:00||America/Thule => (-03:00) Thule ,
         -04:00||America/Anguilla => (-04:00) Anguilla ,
         -04:00||America/Antigua => (-04:00) Antigua ,
         -04:00||America/Aruba => (-04:00) Aruba ,
         -04:00||America/Barbados => (-04:00) Barbados ,
         -04:00||America/Blanc-Sablon => (-04:00) Blanc-Sablon ,
         -04:00||America/Boa_Vista => (-04:00) Boa_Vista ,
         -04:00||America/Campo_Grande => (-04:00) Campo_Grande ,
         -04:00||America/Caracas => (-04:00) Caracas ,
         -04:00||America/Cuiaba => (-04:00) Cuiaba ,
         -04:00||America/Curacao => (-04:00) Curacao ,
         -04:00||America/Detroit => (-04:00) Detroit ,
         -04:00||America/Dominica => (-04:00) Dominica ,
         -04:00||America/Grand_Turk => (-04:00) Grand_Turk ,
         -04:00||America/Grenada => (-04:00) Grenada ,
         -04:00||America/Guadeloupe => (-04:00) Guadeloupe ,
         -04:00||America/Guyana => (-04:00) Guyana ,
         -04:00||America/Havana => (-04:00) Havana ,
         -04:00||America/Indiana/Indianapolis => (-04:00) Indiana/Indianapolis ,
         -04:00||America/Indiana/Marengo => (-04:00) Indiana/Marengo ,
         -04:00||America/Indiana/Petersburg => (-04:00) Indiana/Petersburg ,
         -04:00||America/Indiana/Vevay => (-04:00) Indiana/Vevay ,
         -04:00||America/Indiana/Vincennes => (-04:00) Indiana/Vincennes ,
         -04:00||America/Indiana/Winamac => (-04:00) Indiana/Winamac ,
         -04:00||America/Iqaluit => (-04:00) Iqaluit ,
         -04:00||America/Kentucky/Louisville => (-04:00) Kentucky/Louisville ,
         -04:00||America/Kentucky/Monticello => (-04:00) Kentucky/Monticello ,
         -04:00||America/Kralendijk => (-04:00) Kralendijk ,
         -04:00||America/La_Paz => (-04:00) La_Paz ,
         -04:00||America/Lower_Princes => (-04:00) Lower_Princes ,
         -04:00||America/Manaus => (-04:00) Manaus ,
         -04:00||America/Marigot => (-04:00) Marigot ,
         -04:00||America/Martinique => (-04:00) Martinique ,
         -04:00||America/Montserrat => (-04:00) Montserrat ,
         -04:00||America/Nassau => (-04:00) Nassau ,
         -04:00||America/New_York => (-04:00) New_York ,
         -04:00||America/Nipigon => (-04:00) Nipigon ,
         -04:00||America/Pangnirtung => (-04:00) Pangnirtung ,
         -04:00||America/Port-au-Prince => (-04:00) Port-au-Prince ,
         -04:00||America/Port_of_Spain => (-04:00) Port_of_Spain ,
         -04:00||America/Porto_Velho => (-04:00) Porto_Velho ,
         -04:00||America/Puerto_Rico => (-04:00) Puerto_Rico ,
         -04:00||America/Santo_Domingo => (-04:00) Santo_Domingo ,
         -04:00||America/St_Barthelemy => (-04:00) St_Barthelemy ,
         -04:00||America/St_Kitts => (-04:00) St_Kitts ,
         -04:00||America/St_Lucia => (-04:00) St_Lucia ,
         -04:00||America/St_Thomas => (-04:00) St_Thomas ,
         -04:00||America/St_Vincent => (-04:00) St_Vincent ,
         -04:00||America/Thunder_Bay => (-04:00) Thunder_Bay ,
         -04:00||America/Toronto => (-04:00) Toronto ,
         -04:00||America/Tortola => (-04:00) Tortola ,
         -05:00||America/Atikokan => (-05:00) Atikokan ,
         -05:00||America/Bogota => (-05:00) Bogota ,
         -05:00||America/Cancun => (-05:00) Cancun ,
         -05:00||America/Cayman => (-05:00) Cayman ,
         -05:00||America/Chicago => (-05:00) Chicago ,
         -05:00||America/Eirunepe => (-05:00) Eirunepe ,
         -05:00||America/Guayaquil => (-05:00) Guayaquil ,
         -05:00||America/Indiana/Knox => (-05:00) Indiana/Knox ,
         -05:00||America/Indiana/Tell_City => (-05:00) Indiana/Tell_City ,
         -05:00||America/Jamaica => (-05:00) Jamaica ,
         -05:00||America/Lima => (-05:00) Lima ,
         -05:00||America/Matamoros => (-05:00) Matamoros ,
         -05:00||America/Menominee => (-05:00) Menominee ,
         -05:00||America/North_Dakota/Beulah => (-05:00) North_Dakota/Beulah ,
         -05:00||America/North_Dakota/Center => (-05:00) North_Dakota/Center ,
         -05:00||America/North_Dakota/New_Salem => (-05:00) North_Dakota/New_Salem ,
         -05:00||America/Panama => (-05:00) Panama ,
         -05:00||America/Rainy_River => (-05:00) Rainy_River ,
         -05:00||America/Rankin_Inlet => (-05:00) Rankin_Inlet ,
         -05:00||America/Resolute => (-05:00) Resolute ,
         -05:00||America/Rio_Branco => (-05:00) Rio_Branco ,
         -05:00||America/Winnipeg => (-05:00) Winnipeg ,
         -06:00||America/Bahia_Banderas => (-06:00) Bahia_Banderas ,
         -06:00||America/Belize => (-06:00) Belize ,
         -06:00||America/Boise => (-06:00) Boise ,
         -06:00||America/Cambridge_Bay => (-06:00) Cambridge_Bay ,
         -06:00||America/Costa_Rica => (-06:00) Costa_Rica ,
         -06:00||America/Denver => (-06:00) Denver ,
         -06:00||America/Edmonton => (-06:00) Edmonton ,
         -06:00||America/El_Salvador => (-06:00) El_Salvador ,
         -06:00||America/Guatemala => (-06:00) Guatemala ,
         -06:00||America/Inuvik => (-06:00) Inuvik ,
         -06:00||America/Managua => (-06:00) Managua ,
         -06:00||America/Merida => (-06:00) Merida ,
         -06:00||America/Mexico_City => (-06:00) Mexico_City ,
         -06:00||America/Monterrey => (-06:00) Monterrey ,
         -06:00||America/Ojinaga => (-06:00) Ojinaga ,
         -06:00||America/Regina => (-06:00) Regina ,
         -06:00||America/Swift_Current => (-06:00) Swift_Current ,
         -06:00||America/Tegucigalpa => (-06:00) Tegucigalpa ,
         -06:00||America/Yellowknife => (-06:00) Yellowknife ,
         -07:00||America/Chihuahua => (-07:00) Chihuahua ,
         -07:00||America/Creston => (-07:00) Creston ,
         -07:00||America/Dawson => (-07:00) Dawson ,
         -07:00||America/Dawson_Creek => (-07:00) Dawson_Creek ,
         -07:00||America/Fort_Nelson => (-07:00) Fort_Nelson ,
         -07:00||America/Hermosillo => (-07:00) Hermosillo ,
         -07:00||America/Los_Angeles => (-07:00) Los_Angeles ,
         -07:00||America/Mazatlan => (-07:00) Mazatlan ,
         -07:00||America/Phoenix => (-07:00) Phoenix ,
         -07:00||America/Tijuana => (-07:00) Tijuana ,
         -07:00||America/Vancouver => (-07:00) Vancouver ,
         -07:00||America/Whitehorse => (-07:00) Whitehorse ,
         -08:00||America/Anchorage => (-08:00) Anchorage ,
         -08:00||America/Juneau => (-08:00) Juneau ,
         -08:00||America/Metlakatla => (-08:00) Metlakatla ,
         -08:00||America/Nome => (-08:00) Nome ,
         -08:00||America/Sitka => (-08:00) Sitka ,
         -08:00||America/Yakutat => (-08:00) Yakutat ,
         -09:00||America/Adak => (-09:00) Adak 
    );

I have used it in many projects, sharing to help you. Thanks for asking this question.