List of Supported Timezones
PHP Manual

America

America
America/Adak America/Anchorage America/Anguilla America/Antigua America/Araguaina
America/Argentina/Buenos_Aires America/Argentina/Catamarca America/Argentina/ComodRivadavia America/Argentina/Cordoba America/Argentina/Jujuy
America/Argentina/La_Rioja America/Argentina/Mendoza America/Argentina/Rio_Gallegos America/Argentina/San_Juan America/Argentina/San_Luis
America/Argentina/Tucuman America/Argentina/Ushuaia America/Aruba America/Asuncion America/Atikokan
America/Atka America/Bahia America/Barbados America/Belem America/Belize
America/Blanc-Sablon America/Boa_Vista America/Bogota America/Boise America/Buenos_Aires
America/Cambridge_Bay America/Campo_Grande America/Cancun America/Caracas America/Catamarca
America/Cayenne America/Cayman America/Chicago America/Chihuahua America/Coral_Harbour
America/Cordoba America/Costa_Rica America/Cuiaba America/Curacao America/Danmarkshavn
America/Dawson America/Dawson_Creek America/Denver America/Detroit America/Dominica
America/Edmonton America/Eirunepe America/El_Salvador America/Ensenada America/Fort_Wayne
America/Fortaleza America/Glace_Bay America/Godthab America/Goose_Bay America/Grand_Turk
America/Grenada America/Guadeloupe America/Guatemala America/Guayaquil America/Guyana
America/Halifax America/Havana America/Hermosillo America/Indiana/Indianapolis America/Indiana/Knox
America/Indiana/Marengo America/Indiana/Petersburg America/Indiana/Tell_City America/Indiana/Vevay America/Indiana/Vincennes
America/Indiana/Winamac America/Indianapolis America/Inuvik America/Iqaluit America/Jamaica
America/Jujuy America/Juneau America/Kentucky/Louisville America/Kentucky/Monticello America/Knox_IN
America/La_Paz America/Lima America/Los_Angeles America/Louisville America/Maceio
America/Managua America/Manaus America/Marigot America/Martinique America/Mazatlan
America/Mendoza America/Menominee America/Merida America/Mexico_City America/Miquelon
America/Moncton America/Monterrey America/Montevideo America/Montreal America/Montserrat
America/Nassau America/New_York America/Nipigon America/Nome America/Noronha
America/North_Dakota/Center America/North_Dakota/New_Salem America/Panama America/Pangnirtung America/Paramaribo
America/Phoenix America/Port-au-Prince America/Port_of_Spain America/Porto_Acre America/Porto_Velho
America/Puerto_Rico America/Rainy_River America/Rankin_Inlet America/Recife America/Regina
America/Resolute America/Rio_Branco America/Rosario America/Santiago America/Santo_Domingo
America/Sao_Paulo America/Scoresbysund America/Shiprock America/St_Barthelemy America/St_Johns
America/St_Kitts America/St_Lucia America/St_Thomas America/St_Vincent America/Swift_Current
America/Tegucigalpa America/Thule America/Thunder_Bay America/Tijuana America/Toronto
America/Tortola America/Vancouver America/Virgin America/Whitehorse America/Winnipeg
America/Yakutat America/Yellowknife      

List of Supported Timezones
PHP Manual