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How Many Time Zones in the USA?

The United States spans a vast geographical area, resulting in multiple time zones. Officially, there are 9 standard time zones in the USA, and 11 when including its territories.

Quick Answer

There are nine standard time zones in the United States. They are Atlantic, Eastern, Central, Mountain, Pacific, Alaskan, and Hawaii-Aleutian, plus the Samoa and Chamorro time zones for its territories. Most of the contiguous U.S. is covered by four zones: Eastern, Central, Mountain, and Pacific.

The 9 Standard US Time Zones

The United States and its territories are spread across 11 time zones. The 9 primary time zones are:

  • Atlantic Standard Time (AST): UTC-4, used in Puerto Rico and the U.S. Virgin Islands.
  • Eastern Standard Time (EST): UTC-5, used by the East Coast.
  • Central Standard Time (CST): UTC-6, covering the central states.
  • Mountain Standard Time (MST): UTC-7, used in the Rocky Mountains region.
  • Pacific Standard Time (PST): UTC-8, used by the West Coast.
  • Alaskan Standard Time (AKST): UTC-9, used in most of Alaska.
  • Hawaii-Aleutian Standard Time (HST): UTC-10, used in Hawaii and parts of the Aleutian Islands.
  • Samoa Standard Time (SST): UTC-11, used in American Samoa.
  • Chamorro Standard Time (ChST): UTC+10, used in Guam.

Conclusion

In total, the USA uses 9 standard time zones, from the Atlantic to beyond the Pacific. This diversity is essential for the functioning of a country that spans such a great width. You can explore these zones visually on our Time Zone Map.

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