Ask a Climatologist: Tallying daylight on the darkest day of the year

Above the Arctic circle, there’s no daylight on the solstice. Farther south, Fairbanks has about 3.5 hours. Anchorage, 5.5 hours and Juneau a bit more than six hours. (Graphic courtesy of Brian Brettschneider)

Alaska marked the solstice early Dec. 21, at 1:44 a.m. So what does that mean for the amount of daylight across the state?

To answer that question, we checked in with Brian Brettschneider, a climatologist in Anchorage who closely tracks Alaska climate data and trends.

He regularly talks with editor Annie Feidt from Alaska’s Energy Desk as part of the segment, Ask a Climatologist.

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Interview transcript:

Brian: If you’re north of the Arctic Circle, north of Kotzebue, there’s no daylight, so no sunrise and sunset. And then once you get south of there, in Fairbanks, you’re at about 3.5 hours. When you get to Anchorage it’s somewhere in the 5.5 hour range and then in Juneau, it’s about six hours, 20 minutes.

Annie: Compare that to a few major cities in the lower 48.

Brian: Places in the northern part of the lower 48, like Seattle or Chicago, you’re looking at 8.5 to 9 hours of daylight. As you get farther south, like say Los Angeles- ten hours; in Miami- 10.5 hours.

Annie: How does the amount of daylight, especially in a place like Utqiagvik (formerly Barrow) affect the climate?

Brian: When the sun is about five degrees above the horizon, it provides essentially no solar energy. And so even though the sun is out and on your skin, you may feel a little warmth, but it provides almost no atmospheric heating. It’s just as likely in Fairbanks, for example, that the high temperature of the day would occur at 2:00 a.m., and the low at 2:00 p.m. There’s really no correlation like you would find in the summer when the sun is high in the sky and the afternoon high temperature is going to be just after that peak solar angle. It could be any time of the day or night once you get a little bit north of Anchorage.

Annie: Does the amount of daylight balance out around the globe over the course of a year?

Brian: That’s a really interesting question because we assume that long days in the summer, short days in the winter and they all average out. It’s actually not entirely true because of the elliptical nature of our orbit and the tilt of our axis, we actually get more daylight in the summer here in Alaska than we have darkness in the winter. So for example in Utqiagvik, formerly Barrow, in the summer they have 82 days where there is no sunset, so 24 hours of daylight, but in the winter they have 64 days with no sunrise, so that’s an 18 day difference. So it’s not fully in balance and that solar equation is actually more heavily weighted toward light than dark here in Alaska.

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Annie Feidt is the Managing Editor for Alaska's Energy Desk, a collaboration between Alaska Public Media in Anchorage, KTOO Public Media in Juneau and KUCB in Unalaska. Her reporting has taken her searching for polar bears on the Chukchi Sea ice, out to remote checkpoints on the Iditarod Trail, and up on the Eklutna Glacier with scientists studying its retreat. Her stories have been heard nationally on NPR and Marketplace. Annie’s career in radio journalism began in 1998 at Minnesota Public Radio, where she produced the regional edition of All Things Considered. She moved to Anchorage in 2004 with her husband, intending to stay in the 49th state just a few years. She has no plans to leave anytime soon. afeidt (at) alaskapublic (dot) org  |  907.550.8443 | About Annie