Alaska Time Zone - Anomalies

Anomalies

The Alaska Time Zone applies to the territory of the state of Alaska east of 169°30′ W. Given that the UTC−9 time corresponds to the solar time at 9 × 15° = 135° W (roughly, Juneau), the westernmost locales of the Alaska Time Zone are off by up to 169°30′ − 135° = 34°30′ from local solar time. This means that when a clock correctly set to Alaska time, at a location just east of 169°30′ W, shows noon, local solar time is actually around 9:42 a.m. When UTC−8 is applied in the summer (because of daylight saving time), this effect becomes even more apparent. For example, on June 12 at noon AKDT, the solar time at the extreme westerly points of the Alaskan time zone will actually be only 8:42 a.m. Very few people however, notice this as these locations are virtually uninhabited, and for the very few people who do live there, the long days in the summer and short days in the winter make the sunrise and sunset times less important than areas closer to the equator. By contrast, in Juneau, which is much closer to the 135° west meridian, mean solar noon occurs around 11:57 a.m., very close to clock noon.

In Anchorage, visitors from more southerly latitudes are often surprised to see the sun set at 11:41 p.m.on the summer solstice, but the actual 'solar time' is 9:41 p.m. This is because at 150° W, Anchorage is a full solar hour behind the legal time zone and observes daylight saving time as well. Some local residents refer to this phenomenon as "double daylight time". In Fairbanks, the same circumstances cause sunset to occur at 12:47 a.m. on the next calendar day. In the winter, even without daylight saving time, another anomaly is that on the winter solstice in Nome, the sunrise is actually after "noon" clock time, at 12:02 p.m., about 4 hours before sunset at 3:56 p.m.

The territory of the state of Alaska spans almost as much longitude as the continental United States (57.5° vs. 57.6°) so the use of two time zones will inevitably lead to some distortions. Alaska would "naturally" fall into four time zones, but political considerations have led to the use of two, leading to the distortions mentioned above.