Alaska Time Zone

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The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time (UTC-9). During Daylight Saving Time, its time offset is only eight hours (UTC-8). The clock time in this zone is based on the mean solar time of the 135th degree meridian west of the Greenwich Observatory.

The zone includes nearly all of the U.S. state of Alaska and is one hour behind the Pacific Time Zone.

standard time: Alaska Standard Time (AKST)
daylight saving: Alaska Daylight Time (AKDT)

The western Aleutians observe Hawaii-Aleutian Time, one or (usually) two hours behind the remainder of the state.

1 History
2 Anomalies
3 Major Metropolitan Areas
4 See also
5 Sources

[edit] History

The original Alaska time zone was actually known as Alaska-Hawaii Standard Time Zone; that zone is now known as Hawaii-Aleutian Time Zone.

The Alaska Time Zone is the same as what the Yukon Standard Time Zone (YST) was. However, the Yukon Territory switched to the Pacific Standard Time Zone in 1975 and the time zone was not used (except for Yakutat) until 1983 when the state of Alaska decided to move most of the state to UTC-9. Prior to that the Alaska Panhandle communities were on the Pacific Time Zone, while most of the interior was on UTC-10. Nome and the Aleutians previously observed Bering Standard Time or UTC-11.

[edit] Anomalies

The Alaska Time Zone is applied to the territory of the state of Alaska to the east of 169° 30' W. Given that the UTC-9 time corresponds to the solar time at 9 x 15° = 135° W (roughly, Juneau), the westernmost locales where Alaska time gets applied are off by 169° 30' - 135° = 34° 30' from their 'physical' time. This means that when a clock correctly set to Alaskan time, at a location just east of 169° 30' W, shows noon, the 'physical' time is actually just 9:42 am. When UTC-8 is applied in the summer, this effect becomes even more apparent, since the solar time at Fresno, California (~120° W) is used. At a (say) July noon, the physical time at the extreme westerly points of the Alaskan time zone will actually be only 8:42 am.