Alaska is known for its long, dark winters. However, not all parts of Alaska experience complete darkness during the winter months. Here is a look at what months different parts of Alaska do not experience 24 hours of darkness.
Anchorage
Anchorage, Alaska’s largest city, does not experience complete darkness during the winter months. Here are the details for Anchorage:
- November – Anchorage starts to experience decreasing daylight in November, but still has over 7 hours of daylight throughout the month.
- December – December 21st is the winter solstice and marks the day with the least amount of daylight. Anchorage has about 5 and a half hours of daylight on December 21st.
- January – Daylight increases slightly in January, with Anchorage getting just over 6 hours of daylight by January 31st.
- February – Continues to see a slow increase in daylight. By the end of February, Anchorage has about 9 and a half hours of daylight.
So while daylight hours are limited, Anchorage gets at least 5 hours of daylight even during the darkest day of the year in December. The months of November through February get progressively more daylight, but never reach complete darkness.
Fairbanks
Fairbanks, located in Alaska’s interior, experiences slightly more darkness than Anchorage in the winter months. Here are the details for Fairbanks:
- November – Fairbanks starts to see decreasing daylight, but still has close to 6 hours of daylight throughout November.
- December – Fairbanks gets down to less than 4 hours of daylight in December. The winter solstice on December 21st has about 3 and a half hours of daylight.
- January – Daylight continues to increase slowly in January, with Fairbanks getting just over 5 hours of daylight by January 31st.
- February – By the end of February, Fairbanks has about 10 hours of daylight.
While darker than Anchorage, Fairbanks still does not reach 24 hours of darkness during the winter months. The darkest day on December 21st still has over 3 hours of daylight.
Barrow
Barrow, the northernmost town in Alaska located above the Arctic Circle, experiences the most darkness. Here are the details for Barrow:
- November – Barrow starts to see a significant decrease in daylight hours in November, but still has over 4 hours of daylight throughout the month.
- December – By December, Barrow is down to less than 2 hours of daylight on its darkest day. The winter solstice on December 21st has about 1 and a half hours of daylight.
- January – Through most of January, Barrow has about 2 hours of daylight per day. However, the last week of January is a period of “civil twilight” with no sunrise/sunset.
- February – Experiences civil twilight through February 11th, followed by increasing daylight hours for the rest of the month.
So while getting down to only 1-2 hours on its darkest days, Barrow does not reach a point of zero daylight or complete 24 hour darkness during the winter.
Comparison of Daylight Hours
To summarize and compare the daylight hours between the 3 Alaskan cities:
| City | Nov Hours | Dec 21 Hours | Jan 31 Hours | Feb 28 Hours |
|---|---|---|---|---|
| Anchorage | 7 | 5.5 | 6 | 9.5 |
| Fairbanks | 6 | 3.5 | 5 | 10 |
| Barrow | 4 | 1.5 | 2 | 10 |
This table shows the daylight hours on sample dates through the winter months for the 3 cities. While daylight decreases significantly, none of the cities experience complete darkness.
Why Alaska does not experience 24 hours of darkness
There are two main reasons why Alaska does not experience periods of 24 hour darkness during the winter months:
- Alaska’s high latitude location – Even Barrow, Alaska at 71°N latitude is still south of the Arctic Circle at 66°N. This means the sun will always rise at least briefly above the horizon each day of the winter.
- Refraction of sunlight – Atmospheric refraction causes the sun to appear slightly higher above the horizon than it actually is. This means the sun may still be visible even when geometrically below the horizon.
So between its latitude allowing brief sunrise/sunsets and refraction extending those periods, the parts of Alaska inhabited by humans do not reach 24 hours of continual darkness.
More on Alaska’s high latitude location
At latitudes above the Arctic Circle like the northern parts of Alaska, the sun does not rise at all for a period around the winter solstice. However, inhabited parts of Alaska sit south of the Arctic Circle so do not experience this complete darkness.
For example, Barrow at 71°N latitude still sees the sun rise briefly above the horizon each day. More southerly cities like Anchorage and Fairbanks have longer periods of sunlight above the horizon. So while daylight hours are very short in the winter, the sun always rises even on the darkest days.
More on refraction of sunlight
Refraction refers to the bending of light as it passes through the atmosphere. This causes the sun to appear slightly higher above the horizon than its true geometric position.
Without refraction, the winter daylight hours in Alaska would be even shorter. But refraction extends the period of visible sunlight by up to a few degrees, giving between 30-60 extra minutes of visible light even when the sun is geometrically just below the horizon.
Between Alaska’s latitude and the effects of refraction, cities in Alaska get at least brief periods of visible sunlight each day of the winter.
Conclusion
In conclusion, while Alaska experiences very limited daylight in the winter months, no major populated areas of Alaska reach 24 hours of continual darkness. The most northern city of Barrow gets down to only 1-2 hours of visible sunlight on the darkest winter days. More southerly cities like Fairbanks and Anchorage get 3-5 hours even on the winter solstice. Refraction of light extends these brief sunny periods a bit further. So the months of November through February see very short, but not completely dark days across Alaska’s inhabited regions.
