Time Zones in the United States

Time Zones Currently Being Used in United States

Offset	Time Zone Abbreviation & Name		Example City	Current Time
UTC -10	HST	Hawaii Standard Time	Honolulu	Thu, 11:23:07 pm
UTC -9	AKST	Alaska Standard Time	Anchorage	Fri, 12:23:07 am
UTC -8	PST	Pacific Standard Time	Los Angeles	Fri, 1:23:07 am
UTC -7	MST	Mountain Standard Time	Salt Lake City	Fri, 2:23:07 am
UTC -6	CST	Central Standard Time	Chicago	Fri, 3:23:07 am
UTC -5	EST	Eastern Standard Time	New York	Fri, 4:23:07 am

How Many Time Zones Are There in the US?

There are 9 time zones by law in the USA and its dependencies. However, adding the time zones of 2 uninhabited US territories, Howland Island and Baker Island, brings the total count to 11 time zones.

The contiguous US has 4 standard time zones. In addition, Alaska, Hawaii, and 5 US dependencies all have their own time zones. As neither Hawaii nor the 5 dependencies use Daylight Saving Time (DST), there are only 6 corresponding DST time zones.

A 12th Time Zone?

Since Howland Island and Baker Island constitute the world's westernmost landmasses in relation to the International Date Line, making them the last places on Earth where any date exists, they are sometimes assigned a theoretical 12th time zone called Anywhere on Earth (AoE).

Generalized Time Zones in United States

Time Zone Abbreviation & Name		Offset	Current Time
PT	Pacific Time	UTC -8:00 / -7:00	Fri, 1:23:07 am
MT	Mountain Time	UTC -7:00 / -6:00	Fri, 2:23:07 am
CT	Central Time	UTC -6:00 / -5:00	Fri, 3:23:07 am
ET	Eastern Time	UTC -5:00 / -4:00	Fri, 4:23:07 am

The time zones in the contiguous US are often referred to by their generic name, without making a difference between standard time and Daylight Saving Time designations. For example, Eastern Time (ET) refers to Eastern Standard Time (EST) or Eastern Daylight Time (EDT), depending on which is currently in use. In practice, this means that the local time in these time zones changes when DST begins and ends.

Note: Local time in these time zones changes when Daylight Saving Time begins and ends.

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Time Zones Not Currently Being Observed in United States

Offset	Time Zone Abbreviation & Name		Commences
UTC -9	HDT	Hawaii-Aleutian Daylight Time	Mar 8, 2026
UTC -8	AKDT	Alaska Daylight Time	Mar 8, 2026
UTC -7	PDT	Pacific Daylight Time	Mar 8, 2026
UTC -6	MDT	Mountain Daylight Time	Mar 8, 2026
UTC -5	CDT	Central Daylight Time	Mar 8, 2026
UTC -4	EDT	Eastern Daylight Time	Mar 8, 2026

The above time zones are used during other parts of the year. They will become active again after the next clock change as Daylight Saving Time begins or ends.

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Time Zones Being Used in Dependencies of United States

Offset	Time Zone Abbreviation & Name		Dependency	Type	Current Time
UTC -12	AoE	Anywhere on Earth	US Minor Outlying Islands	Territory	Thu, 9:23:07 pm
UTC -11	SST	Samoa Standard Time	American Samoa	Unincorp. unorg. territory	Thu, 10:23:07 pm
	SST	Samoa Standard Time	US Minor Outlying Islands	Territory	Thu, 10:23:07 pm
UTC -10	HST	Hawaii Standard Time	US Minor Outlying Islands	Territory	Thu, 11:23:07 pm
UTC -4	AST	Atlantic Standard Time	Puerto Rico	Unincorp. org. territory	Fri, 5:23:07 am
	AST	Atlantic Standard Time	US Virgin Islands	Unincorp. org. territory	Fri, 5:23:07 am
UTC +10	ChST	Chamorro Standard Time	Guam	Unincorp. org. territory	Fri, 7:23:07 pm
	ChST	Chamorro Standard Time	Northern Mariana Islands	Unincorp. org. territory	Fri, 7:23:07 pm
UTC +12	WAKT	Wake Time	US Minor Outlying Islands	Territory	Fri, 9:23:07 pm

The US dependencies don't use DST.

The United States' Time Zone History

The US was divided into 4 standard time zones on November 18, 1883, and jurisdiction for the zones was given to the Interstate Commerce Commission (ICC). Since 1967, the US Department of Transportation (DOT) has been responsible for governing time zones in the country.

Time zones in the USA are defined in the U.S. Code, Title 15, Chapter 6, Subchapter IX - Standard Time. The time zones in the law are defined by their offset from Coordinated Universal Time (UTC).

There are 9 official time zones according to the law. In addition the uninhabited atolls of Baker Island (AoE) and Wake Island (WAKT) add to the time zone count, making 11 the total number of time zones in the US.

Almost all states in the US use Daylight Saving Time (DST). Most of Arizona and Hawaii don't use DST. Indiana introduced DST in 2006.

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