That s because they re blocking depending what browser you re using.
Try this:
$curl = curl_init();
curl_setopt($curl, CURLOPT_USERAGENT, Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.6) Gecko/2009012700 SUSE/3.0.6-1.4 Firefox/3.0.6 );
curl_setopt($curl, CURLOPT_URL, http://apple.accuweather.com/adcbin/apple/Apple_Weather_Data.asp?zipcode=EUR;PT;PO019;REGUA );
$xmlstr = curl_exec($curl);
$xmlobj = simplexml_load_string($xmlstr);
print header("Content-type: text/plain");
print_r($xmlobj);
顺便说一下,在文件中你可以看到“禁止再分配”,所以你可能要寻找一些免版税的天气数据来源。