Current Time in GMT − 10 Zone
About GMT-10
GMT-10 is ten hours behind Greenwich Mean Time. It is known as Hawaii-Aleutian Standard Time (HST). It is used year-round by Hawaii and the Cook Islands. The Aleutian Islands of Alaska use it as their standard winter time, observing DST in the summer. Hawaii does not observe DST.
UTC Offset: GMT-10
What is GMT-10?
GMT-10 means Greenwich Mean Time 10 hours behind the Greenwich meridian, the historical reference line running through the Royal Observatory in London. GMT offsets are the everyday way many countries, broadcasters, and travel timetables describe their local time relative to the UK.
Note that some of the countries listed below sit on GMT-10 for only part of the year: when daylight saving time starts or ends they move one hour, so always check the live local times shown on this page or on each country's own page.
GMT-10 vs UTC-10
For everyday purposes GMT-10 and UTC-10 are the same wall-clock time. GMT is the traditional name based on mean solar time at Greenwich, while UTC is the modern atomic-time standard used by computers and aviation. If you are setting a meeting or catching a flight, either works; if you are configuring a server, use UTC-10.
Time & Daylight in GMT-10
Time Difference Between GMT-10 and Major Cities
Live local time and the difference from GMT-10 right now.
Current time shown is based on the representative IANA zone: Etc/GMT+10
GMT-10: The Fixed Offset and the Zones That Call It Home
GMT-10 is a fixed UTC offset of negative ten hours, meaning local clocks are always ten hours behind Coordinated Universal Time (UTC). While UTC and GMT are technically different references, they read identically on a clock, so a GMT-10 offset is the same as UTC-10. This offset is used by several Pacific islands and a slice of the United States, but not all regions on this offset stay there year-round due to daylight saving time.
What a Fixed UTC Offset Means vs. a Named Time Zone
A fixed UTC offset like GMT-10 is simply a number: local time is UTC minus ten hours. It does not change with seasons. In contrast, a named time zone (e.g., Hawaii-Aleutian Standard Time, HAST) may shift offsets during daylight saving time (DST). For example, the U.S. state of Hawaii uses Hawaii-Aleutian Standard Time (HAST) which is fixed at GMT-10 all year, while the Aleutian Islands (America/Adak) use HAST in winter but switch to Hawaii-Aleutian Daylight Time (HADT, GMT-9) in summer. So the list of countries and territories on GMT-10 is not static; it changes as DST-observing regions move on and off this offset seasonally.
Which Regions and Cities Sit at GMT-10
As of standard time (winter in the Northern Hemisphere), the following major regions and cities are on GMT-10:
- Cook Islands (Pacific/Rarotonga) – The entire country, including the capital Avarua on Rarotonga, uses GMT-10 year-round. No DST.
- French Polynesia (Pacific/Tahiti) – The Society Islands, Tuamotu, and most inhabited islands use GMT-10 year-round. The capital Papeete on Tahiti is the largest city. The Marquesas Islands use a different offset (GMT-9:30) and Gambier Islands use GMT-9.
- United States – Hawaii (Pacific/Honolulu, US/Hawaii) uses GMT-10 year-round. Also, the Aleutian Islands west of 169°30′W (America/Adak) use GMT-10 during standard time (winter), but switch to GMT-9 during daylight saving time (spring to fall). The city of Adak is the main settlement in this DST-observing part of Alaska.
Representative cities at GMT-10: Adak (Alaska, during standard time), Honolulu (Hawaii), Rarotonga (Cook Islands), Tahiti (French Polynesia).
Practical Scheduling Notes
When scheduling across time zones, remember that GMT-10 is one of the last time zones to start a new day. At 12:00 UTC, it is 02:00 in GMT-10. This offset is 5 hours behind U.S. Eastern Time (EST) during standard time (e.g., 12:00 EST = 07:00 GMT-10) and 6 hours behind Eastern Daylight Time (EDT). For calls between Honolulu and Tokyo (UTC+9), the time difference is 19 hours (Honolulu is 19 hours behind Tokyo). The military designation for this offset is 'W' (Whiskey) time zone. Zulu (Z) time is another name for UTC, so Zulu time equals GMT-10 plus ten hours.
Daylight Saving Time and the Shifting Country List
Because the Aleutian Islands (America/Adak) observe DST, they move from GMT-10 (winter) to GMT-9 (summer). Therefore, during summer months, the only U.S. territory on GMT-10 is Hawaii. The Cook Islands and French Polynesia do not observe DST, so they remain on GMT-10 year-round. This means the list of countries on this offset is not static; it shrinks to two (Cook Islands and French Polynesia) during the Northern Hemisphere summer, and expands to three (plus the Aleutians) during winter.
Frequently Asked Questions
Is GMT-10 the same as UTC-10?
Yes. GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) are different standards but are within a second of each other and read the same on a clock. So GMT-10 and UTC-10 are interchangeable for everyday timekeeping.
Which US states are on GMT-10?
Hawaii is on GMT-10 year-round. Parts of Alaska, specifically the Aleutian Islands west of 169°30′W, are on GMT-10 during standard time (winter) but switch to GMT-9 during daylight saving time.
Does French Polynesia observe daylight saving time?
No. French Polynesia (including Tahiti) stays on GMT-10 all year. The Marquesas Islands use GMT-9:30, and the Gambier Islands use GMT-9, but these are separate offsets.
What is the military time zone letter for GMT-10?
The military time zone letter for GMT-10 is 'W' (Whiskey). Zulu (Z) is used for UTC.
What is the time difference between GMT-10 and Tokyo?
Tokyo is at UTC+9. The difference is 19 hours: when it is noon in Tokyo, it is 5:00 PM the previous day in GMT-10 (e.g., 12:00 Tokyo = 17:00 GMT-10).
Why does the list of countries on GMT-10 change?
The list changes because the Aleutian Islands (America/Adak) observe daylight saving time. During winter they are on GMT-10, but in summer they shift to GMT-9. So in summer, only the Cook Islands and French Polynesia (and Hawaii) remain on GMT-10.