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). Canada follows United States daylight 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.

United States

The following states or areas are part of the Pacific Time Zone:

• California
• Washington
• Oregon - all, except for northern three quarters of Malheur County, on Idaho border
• Nevada - all, except for the border towns of West Wendover (near Utah) and Jackpot (near Idaho)
• Idaho - northern half, north of Salmon River

Arizona is in the Mountain Time Zone but does not observe daylight saving time (except in the Navajo Nation), so it is effectively on Pacific Daylight Time from mid-March to early November.

Canada

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 and Creston), all of Yukon and Tungsten, Northwest Territories.

Mexico

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.

Daylight time

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, the local time changes from PST to PDT at 02:00 LST to 03:00 LDT are on the second Sunday in March and the time returns at 02:00 LDT to 01:00 LST on the first Sunday in November. In Mexico, the previous dates are still in effect.

Major cities

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

• Los Angeles, California, USA
• San Diego, California, USA
• San Jose, California, USA
• Tijuana, Baja California, Mexico

Over 700,000 residents

• San Francisco, California, USA
• Mexicali, Baja California, Mexico

Over 400,000 residents

• Ensenada, Baja California, Mexico
• Fresno, California, USA
• Las Vegas, Nevada, USA
• Long Beach, California, USA
• Oakland, California, USA
• Portland, Oregon, USA
• Seattle, Washington, USA
• Sacramento, California, USA
• Surrey, British Columbia, Canada
• Vancouver, British Columbia, Canada

Over 200,000 residents

• Anaheim, California, USA
• Bakersfield, California, USA
• Burnaby, British Columbia, Canada
• Fremont, California, USA
• Henderson, Nevada, USA
• Irvine, California, USA
• Modesto, California, USA
• Reno, Nevada, USA
• Riverside, California, USA
• Santa Ana, California, USA
• Spokane, Washington, USA
• Stockton, California, USA
• Tacoma, Washington, USA

References

Sources

• 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
• PST Pacific Standard Time