Pacific Time Zone

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 degree 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" (Zona Noroeste), 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

In the United States, the states of Washington and California are located entirely within the Pacific Time Zone. Nearly all of Nevada, except for the towns of West Wendover and Jackpot, is on Pacific Time. Additionally, all of Oregon except for the greater part of Malheur County and the northern part of Idaho (the Idaho Panhandle) are also in the zone. The exact specification for the location of time zones and the dividing line between zones is set forth in the Code of Federal Regulations at 49 CFR 71. [The specification for the Pacific Time Zone as it pertains to the United States is set forth at 49 CFR 71.10, and is listed in [http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/49cfr71.10.htm Text] and [http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/49cfr71.10.pdf pdf] formats.
The boundary between Pacific and Mountain in the United States is set forth at 49 CFR 71.9, and is listed in [http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/49cfr71.9.htm text] and [http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/49cfr71.9.pdf pdf] formats.]

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 the Yukon Territory and Tungsten, Northwest Territories.

Mexico

In Mexico, the state of Baja California is wholly within and the only part of Mexico in the Northwest Zone. Also the westernmost of the Revillagigedo Islands (Colima), Clarion Island uses the Northwest Zone.

Daylight time

During summer months, Sonora and most of Arizona, which is in the Mountain time zone (Pacific zone for Sonora) but does not observe DST, they are 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 2007, the local time changes from PST to PDT at 02:00 LST to 03:00 LDT on the second Sunday in March and returns at 02:00 LDT to 01:00 LST on the first Sunday in November, except in Mexico, where the previous dates are still in effect.

Major cities

A rough estimation of the population of the entire time zone is 53,462,949. That is, the populations of Washington, Oregon, Nevada, California, Baja California, British Columbia, and Yukon Territory combined.

Over 1,000,000 residents
*Los Angeles, California, USA
*San Diego, California, USA
*Tijuana, Baja California, Mexico

Over 700,000 residents
*San Francisco, California, USA
*San Jose, 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
*Vancouver, British Columbia, Canada

Over 200,000 residents
*Anaheim, California, USA
*Bakersfield, California, USA
*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
*Victoria, British Columbia, Canada

References

ources

* [http://www.time.gov/timezone.cgi?Pacific/d/-8/java The official U.S. time for the Pacific Time Zone]
* [http://time5.nrc.ca/webclock_e.shtml Official times across Canada]
* [http://www.travel.com.hk/region/timezone.htm World time zone map]
* [http://geography.about.com/library/misc/ntimezones.htm U.S. time zone map]
* [http://aa.usno.navy.mil/faq/docs/us_tzones History of U.S. time zones and UTC conversion]
* [http://www.worldtimezone.com/time-canada12.html Canada time zone map]
* [http://timeanddate.com/worldclock/full.html Time zones for major world cities]
* [http://www.pst.net PST Pacific Standard Time]