| Country: | United States |
|---|---|
| Long Name: | United States of America |
| Abbreviations: | US, USA |
| Capital: | Washington DC |
| Time Zones: | 6 (Main Country) |
| Total Time Zones: | 12 (with dependencies) |
| Dial Code: | +1 |
Time Zones Currently Being Used in United States
| Offset | Time Zone Abbreviation & Name | Example City | Current Time | |
|---|---|---|---|---|
| UTC -10 | HST | Hawaii Standard Time | Honolulu | 水曜日, 8時58分20秒 |
| UTC -9 | AKST | Alaska Standard Time | Anchorage | 水曜日, 9時58分20秒 |
| UTC -8 | PST | Pacific Standard Time | Los Angeles | 水曜日, 10時58分20秒 |
| UTC -7 | MST | Mountain Standard Time | Salt Lake City | 水曜日, 11時58分20秒 |
| UTC -6 | CST | Central Standard Time | Chicago | 水曜日, 12時58分20秒 |
| UTC -5 | EST | Eastern Standard Time | New York | 水曜日, 13時58分20秒 |
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 | 水曜日, 10時58分20秒 |
| MT | Mountain Time | UTC -7:00 / -6:00 | 水曜日, 11時58分20秒 |
| CT | Central Time | UTC -6:00 / -5:00 | 水曜日, 12時58分20秒 |
| ET | Eastern Time | UTC -5:00 / -4:00 | 水曜日, 13時58分20秒 |
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.
Time Zones Not Currently Being Observed in United States
| Offset | Time Zone Abbreviation & Name | Commences | |
|---|---|---|---|
| UTC -9 | HDT | Hawaii-Aleutian Daylight Time | 2025年3月9日 (日) |
| UTC -8 | AKDT | Alaska Daylight Time | 2025年3月9日 (日) |
| UTC -7 | PDT | Pacific Daylight Time | 2025年3月9日 (日) |
| UTC -6 | MDT | Mountain Daylight Time | 2025年3月9日 (日) |
| UTC -5 | CDT | Central Daylight Time | 2025年3月9日 (日) |
| UTC -4 | EDT | Eastern Daylight Time | 2025年3月9日 (日) |
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.
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 | 水曜日, 6時58分20秒 |
| UTC -11 | SST | Samoa Standard Time | American Samoa | Unincorp. unorg. territory | 水曜日, 7時58分20秒 |
| SST | Samoa Standard Time | US Minor Outlying Islands | Territory | 水曜日, 7時58分20秒 | |
| UTC -10 | HST | Hawaii Standard Time | US Minor Outlying Islands | Territory | 水曜日, 8時58分20秒 |
| UTC -4 | AST | Atlantic Standard Time | Puerto Rico | Unincorp. org. territory | 水曜日, 14時58分20秒 |
| AST | Atlantic Standard Time | US Virgin Islands | Unincorp. org. territory | 水曜日, 14時58分20秒 | |
| UTC +10 | ChST | Chamorro Standard Time | Guam | Unincorp. org. territory | 木曜日, 4時58分20秒 |
| ChST | Chamorro Standard Time | Northern Mariana Islands | Unincorp. org. territory | 木曜日, 4時58分20秒 | |
| UTC +12 | WAKT | Wake Time | US Minor Outlying Islands | Territory | 木曜日, 6時58分20秒 |
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.
Time Zone News
- 2024/12/17 – Will Trump End DST?
- 2024/10/07 – DST Ends in the US
- 2024/09/10 – Hate Clock Changes?
- 2024/02/12 – DST 2024 Starts in the USA
- 2023/11/28 – DST Ends in USA & Canada 2023: Still No Law for Permanent DST
More Information
- Time Zone Converter
- Meeting Planner
- Event Time Announcer/Fixed Time
- Time Zone Abbreviations
- Time Zone News
- Daylight Saving Time
Time Zone Map
