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.
In the United States and Canada, this time zone is generically called Pacific Time (PT). Specifically, it is Pacific Standard Time (PST) when observing standard time (Winter), and Pacific Daylight Time (PDT) when observing daylight saving time (Summer). Most of Canada uses daylight saving time. In Mexico the UTC-8 time zone is known as the Northwest Zone, which formerly was synchronized with the U.S. PDT daylight saving schedule.
The zone is one hour ahead of the Alaska Time Zone, one hour behind the Mountain Time Zone and three hours behind the Eastern Time Zone.
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The following states or areas are part of the Pacific Time Zone:
Arizona is in the Mountain Time Zone but does not observe daylight saving time (except in the Navajo Nation), so while technically it is on Mountain Standard Time, it is effectively on Pacific Daylight Time from mid-March to early November.
In Canada, Pacific Time includes almost all of the province of British Columbia (except for the Highway 95 corridor and portions around 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 PST. Also the westernmost of the Revillagigedo Islands, Clarion Island (in the state of Colima), observes PST.
During summer months, most of Arizona, which is in the Mountain time zone but does not observe DST, is on the same time as neighboring states to the west which are on Pacific Daylight Time.
Through 2006, the local time (PST, UTC-8) changed to 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.
A rough estimate of the population of the entire time zone is 53 million (i.e., the populations of Washington, Oregon, Nevada, California, Baja California, British Columbia, and the Yukon combined).
Over 1,000,000 residents
Over 800,000 residents
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Over 200,000 residents
| Hours from GMT | Standard time | Daylight saving | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| –10 | Hawaii-Aleutian | ||||||||||
| –9 | Alaska | Hawaii-Aleutian | |||||||||
| –8 | Pacific | Alaska | |||||||||
| –7 | Mountain | Pacific | |||||||||
| –6 | Central | Mountain | |||||||||
| –5 | Eastern | Central | |||||||||
| –4 | Atlantic | Eastern | |||||||||
| –3:30 | Newfoundland | ||||||||||
| –3 | Saint Pierre and Miquelon | Atlantic | |||||||||
| –2:30 | Newfoundland | ||||||||||
| –2 | Saint Pierre and Miquelon | ||||||||||
| See also: Time in Canada • Time in Mexico • Time in the United States | |||||||||||