List of Supported Timezones
PHP Manual

Pacific

Pacific
Pacific/Apia Pacific/Auckland Pacific/Bougainville Pacific/Chatham
Pacific/Chuuk Pacific/Easter Pacific/Efate Pacific/Enderbury
Pacific/Fakaofo Pacific/Fiji Pacific/Funafuti Pacific/Galapagos
Pacific/Gambier Pacific/Guadalcanal Pacific/Guam Pacific/Honolulu
Pacific/Johnston Pacific/Kiritimati Pacific/Kosrae Pacific/Kwajalein
Pacific/Majuro Pacific/Marquesas Pacific/Midway Pacific/Nauru
Pacific/Niue Pacific/Norfolk Pacific/Noumea Pacific/Pago_Pago
Pacific/Palau Pacific/Pitcairn Pacific/Pohnpei Pacific/Port_Moresby
Pacific/Rarotonga Pacific/Saipan Pacific/Tahiti Pacific/Tarawa
Pacific/Tongatapu Pacific/Wake Pacific/Wallis  

List of Supported Timezones
PHP Manual