Pacific daylight time
The Pacific Time Zone observes standard time by subtracting eight hours from Coordinated Universal Time (UTC−8). The clock time in this zone is based on the mean solar time of the 120th meridian west of the Greenwich Observatory. During daylight saving time, its time offset is UTC−7 and is thus based on the mean solar time of the 105th meridian west of the Greenwich Observatory.
In the United States and Canada, this time zone is generically called the Pacific Time Zone (PTZ). Specifically, it uses Pacific Standard Time (PST) - Pacific Time (PT) - when observing standard time (mid-fall through late winter), and Pacific Daylight Time (PDT) - Mountain Time (MT) - when observing daylight saving time (late winter through mid-fall). Most of Canada uses daylight saving time. In Mexico the UTC−8 time zone is known as the Northwest Zone, which is synchronized with the U.S. PDT daylight saving schedule.
The following states or areas are part of the Pacific Time Zone:
- California - all.
- Washington - all.
- Oregon – all, except for most of Malheur County, on the Idaho border (the dividing line goes through the southwest corner of township 35 S, range 37 E, and lies at a latitude of approximately 42.4507448 N).
- Nevada – all, except for the border town of West Wendover (near Utah), which observes the Mountain Time Zone. Also, the border town of Jackpot (near Idaho) unofficially observes Mountain Time.
- Idaho – northern half, north of the Salmon River.
Most of Arizona lies in the Mountain Time Zone but does not observe daylight saving time. As a result of not observing daylight saving time, most of the state observes Mountain Standard Time (which is in line with Pacific Daylight Time) during the spring, summer and autumn months. The Navajo Nation, most of which lies within Arizona, does observe daylight saving time, although the Hopi Nation, as well as some Arizona state offices lying within the Navajo Nation, do not.
The town of Hyder, Alaska is officially in the Alaska Time Zone, but most of the town uses the Pacific Time Zone since much of its community is dependent on nearby Stewart, British Columbia, which is in the Pacific Time Zone. The United States Post Office in Hyder strictly adheres to Alaska Time.
In Canada, Pacific Time includes almost all of the province of British Columbia (except for the Highway 95 corridor and portions around Tumbler Ridge, Fort St. John, Dawson Creek, Golden and Creston), all of Yukon and Tungsten, Northwest Territories.
In Mexico, the state of Baja California is completely within and the only part of Mexico in the Pacific time zone. The westernmost of the Revillagigedo Islands, Clarion Island (in the state of Colima), observes mountain standard time.
Through 2006, the local time (PST, UTC−8) changed to daylight time (PDT, UTC−7) at 02:00 LST (local standard time) to 03:00 LDT (local daylight time) on the first Sunday in April, and returned at 02:00 LDT to 01:00 LST on the last Sunday in October.
Effective in the US in 2007 as a result of the Energy Policy Act of 2005, the local time changes from PST to PDT at 02:00 LST to 03:00 LDT on the second Sunday in March and the time returns at 02:00 LDT to 01:00 LST on the first Sunday in November. Canada would also acknowledge this change. In Mexico, beginning in 2010, the portion of the country in this time zone uses the extended dates, as do some other parts. The vast majority of Mexico, however, still uses the old dates.
- Effects of time on North American broadcasting
- The official U.S. time for the Pacific Time Zone
- Official times across Canada
- World time zone map
- U.S. time zone map
- History of U.S. time zones and UTC conversion
- Canada time zone map
- Time zones for major world cities
|Time zone||Hours from UTC: Standard time||Hours from UTC: Daylight saving|
|Hawaii-Aleutian||–10||–9 (Alaska portion only)|
|Saint Pierre and Miquelon||–3||–2|