The amount of continuous darkness experienced in Alaska varies dramatically depending on the specific location within the state’s vast geography. Because Alaska extends across many degrees of latitude, the experience of winter daylight ranges from a temporary period of continuous darkness in the far north to merely very short days in the southern regions. The term “dark days” is often used to describe the phenomenon where the sun does not fully rise above the horizon, but this is a geographically isolated event in the state. The answer to how many dark days Alaska has depends entirely on whether a location is north of a specific line on the globe.
Defining the Polar Night Phenomenon
The extreme difference in daylight hours across Alaska is a direct consequence of the Earth’s axial tilt. The planet’s axis is angled about 23.5 degrees, meaning that during the Northern Hemisphere winter, the Arctic region is tilted away from the sun. This geometry drives the seasonal light cycle.
Polar Night is defined as a period lasting more than 24 consecutive hours during which the sun does not rise above the horizon. This phenomenon occurs exclusively within the Arctic Circle, a line of latitude at approximately 66.5 degrees North. Locations just south of this line experience very short days, as the sun briefly crests the horizon daily, separating the true period of continuous darkness from simply having low daylight hours.
The Specifics of Utqiagvik
The most definitive answer to how many dark days there are in Alaska is found in Utqiagvik, the nation’s northernmost city, located deep within the Arctic Circle. Residents experience the Polar Night, a continuous period of darkness lasting approximately 65 to 67 days each year. This period typically begins when the sun sets for the last time in mid-November (around November 18th or 19th) and does not rise again until late January (usually January 22nd or 23rd).
Even during this long stretch, the sky is not perpetually pitch black because of civil twilight. Civil twilight occurs when the sun is between 0 and 6 degrees below the horizon, allowing its light to be refracted through the atmosphere. This refraction creates a pale, diffused light at midday, appearing similar to a perpetual dawn or dusk.
At the start of the Polar Night in November, this civil twilight can last for about six hours around solar noon. However, as the Earth moves closer to the winter solstice in December, the sun sinks farther below the horizon, and the duration of twilight decreases. By the winter solstice, the period of civil twilight is reduced to just three hours, before slowly beginning to lengthen again as the sun prepares for its return in January.
Light Conditions Across Other Regions
The vast majority of Alaska, including its largest population centers, is located south of the Arctic Circle and does not experience the Polar Night. These areas instead endure extremely short daylight hours, with the sun still rising and setting daily.
Fairbanks, a major interior city, is located close to the Arctic Circle and has some of the shortest days outside of the Polar Night zone. On the winter solstice, Fairbanks experiences only about three hours and forty-two minutes of true daylight. The sun rises late, around 10:50 a.m., and sets early, by 2:41 p.m., but it does complete a full arc above the horizon.
Moving further south, the light conditions improve noticeably. Anchorage, the state’s largest city, sees a more moderate five hours and twenty-eight minutes of daylight on the shortest day of the year. The sun rises just after 10:00 a.m. and sets before 4:00 p.m., a much less extreme schedule than the far north.
Juneau, located in the Panhandle, is the southernmost of the major cities and experiences the least extreme light variation. On the winter solstice, Juneau still receives about six hours and twenty-two minutes of daylight. This illustrates that for most Alaskans, the winter is characterized by a temporary period of very short days, not the continuous darkness of the Polar Night.