Earning daylight: A look at Alaska's long summer days
The midnight sun isn't just an experience but a reality here in Alaska as we continue our march towards summer. With each passing day, nights are hard to come by, as many areas are gaining well over five minutes of daylight a day.
It's clear to see just how much longer the days are getting when looking at data for April 8 provided by TimeandDate:
- Juneau gains 5:04 seconds with a day length of 13:49:13
- Anchorage gains 5:44 seconds with a day length of 14:02:47
- Fairbanks gains 6:48 seconds with a day length of 14:23:52
- Amatignak Island (Alaska's southernmost point) gains 3:51 seconds with a day length of 13:25:06
- Attu (Alaska's westernmost point) gains 4:06 with a day length of 13:30:18
- Utqiagvik (Alaska's northernmost point) gains 9:53 seconds with a day length of 15:22:07
One could call it a treat that we get to experience here in the Last Frontier, especially considering the long and cold darkness that drives many indoors during the winter. For many Alaskans longer days are already here, but some of us will soon see 24 hours of daylight. Utqiagvik is only seeing 15 hours of daylight right now, but on May 12 the sun will rise and not dip below the horizon again until Aug. 2.
So what's going on, and why does this cycle always bring polar nights for 65 days and then the midnight sun as summer approaches? The answer lies in the Earth's 365-day journey around the sun while tilted at about 23 degrees. This tilt keeps our planet pointing in the same direction all year long as we complete the journey. This means that in the summertime, the northern hemisphere is pointed directly at the sun and the southern hemisphere is pointed away from the sun. That means that as we experience warmer temperatures in the northern hemisphere, the southern hemisphere is locked into winter.
As the Earth continues the journey around the sun, there comes a point where the northern hemisphere is at its maximum tilt toward the sun. This day, the summer solstice, falls on June 20 or June 21. Depending on where you live in the state, it makes a huge difference in how much daylight you get to experience during the summer months.
While not all of the state experiences 24 hours of daylight, many parts of the state still see enough light all day for people to function outdoors. This is where the twilight phases come into play, which can trick us into thinking that there truly is 24 hours of daylight. According to earthsky.org, twilight is when the sun is below the horizon, but the scattering of the sun's rays through the Earth's atmosphere give off orange and pinkish colors.
If the Earth had no atmosphere, we would have neither a twilight nor a blue sky, so we can thank our Earth's atmosphere for giving Southcentral Alaska a seemingly longer day even though the sun has already set.
Daylight can be tricky business, due in large part to the numerous stages we go through: dawn and dusk, civil twilight, nautical twilight, or astronomical twilight. Each stage of twilight represents a different moment in our journey from day to night.
Civil twilight starts at sunset and last through the time the sun is 6 degrees below the horizon This is also known as dusk, where there is still enough light to see when outdoors, with only the brightest starts visible in the sky. Some lights on vehicles will illuminate the street, but for the most part civil twilight is the time when you know you need to begin wrapping up your time outdoors unless you have artificial light to carry on.
Nautical twilight can be dated back to when sailors used the stars for navigation. During this twilight phase you'll probably need some form of light to see easily, as the sky continues to grow darker. By definition, nautical twilight ends when the sun is 12 degrees below the horizon.
Astronomical twilight is the point when the sky still has little light in the sky, but not necessarily truly dark. It can be defined as the last glimpse of light before darkness fully envelops the region.
Twilight is best seen from space, as you can see the gradual transition from daylight to night with the three phases intermingled in between. These phases, seen in all Alaska areas south of the Arctic Circle, experience them during longer days. This is when we can be tricked into thinking it's daylight even though the sun has already set.
Editor's note: A graphic in an earlier version of this story had a typo that misstated the number of daylight hours in Juneau. This has been updated.
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