The Pacific Time Zone (PT) is one of the four major time zones used in the contiguous United States. Known for encompassing the bustling West Coast cities, it plays a vital role in American timekeeping and commerce.

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What is the Pacific Time Zone?

  • The Pacific Time Zone is one of the nine standard time zones used across the United States and its territories.
  • It was introduced in the late 19th century alongside the other major U.S. time zones.

States and Regions in PT

  • Entirely in PT: California, Washington
  • Mostly in PT: Nevada, Oregon
  • Partially in PT: Idaho Panhandle (10 counties)
  • Beyond the U.S.:
    • Parts of British Columbia and Yukon in Canada
    • Baja California and Clarion Island in Mexico

Time Zone Basics

The Pacific Time Zone is home to major cities and metro areas:

  • Los Angeles, California – Population over 4 million
  • Seattle, Washington
  • Las Vegas, Nevada
  • Portland, Oregon

The largest metro area in the zone is the Greater Los Angeles Area.

Why Standard Time Zones Were Introduced

Before 1883, cities used the sun’s position for local time, creating confusion across regions.

  • Railroads needed a consistent system for schedules.
  • Initially, there were over 100 railroad time zones.
  • On November 18, 1883, four U.S. time zones were introduced to simplify national timekeeping:
    • Pacific, Mountain, Central, Eastern

How the Pacific Time Zone Works

  • PST (Pacific Standard Time): UTC-8, used from November to March
  • PDT (Pacific Daylight Time): UTC-7, used from March to November during daylight savings

Though some states straddle zones, California and Washington fully observe PT year-round.

Daylight Saving in PT

  • Established in 1966 by the Uniform Time Act
  • Extended in 2005 under the Energy Policy Act
  • Starts: Second Sunday in March
  • Ends: First Sunday in November
  • All regions in PT, including Canadian and Mexican areas, follow the same DST schedule

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