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/Salta 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/Santarem
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