Why doesn't the sun set in Alaska?

Parts of Alaska lie north of the Arctic Circle (66.5°N). During the northern summer, Earth's 23.5° axial tilt keeps the North Pole continuously pointed toward the Sun, so any location inside the Arctic Circle stays in sunlight 24 hours a day for weeks or months at a time. The same tilt produces an equally long polar night in the following winter.

How many days does the sun not set in Alaska?

In Utqiaġvik (formerly Barrow), the northernmost city in Alaska, the sun does not set for roughly 84 days—from around May 11 to August 2. Below the Arctic Circle the effect is smaller but still dramatic: places like Fairbanks get more than 21 hours of daylight in midsummer, while Anchorage gets about 19 hours.

Where exactly in Alaska does the sun not set?

Only the parts of Alaska that lie inside the Arctic Circle, i.e. north of latitude 66.5°N. That includes Utqiaġvik, Kaktovik and the North Slope. The state's major cities—Anchorage, Fairbanks, Juneau—lie south of the Arctic Circle and do see brief nights even in midsummer, though daylight stretches to roughly 19–22 hours.

What is Earth's axial tilt and how does it cause this?

Earth's spin axis is tilted by 23.5° relative to the plane of its orbit around the Sun. As Earth orbits, this fixed tilt means the North Pole sometimes leans toward the Sun (northern summer) and sometimes away (northern winter). When the pole is tilted toward the Sun, the whole region within 23.5° of the pole—the Arctic Circle—stays in continuous daylight.

Does the sun ever set in Alaska in winter?

Yes—dramatically so. The same axial tilt that gives Utqiaġvik 84 days of midnight sun also gives it about 65 days of polar night each winter, when the sun never rises above the horizon. The northernmost parts of Alaska experience extreme contrast between summer's endless daylight and winter's endless twilight.

Why Doesn't The Sun Go Down In Alaska For More Than 2 Months?

Table of Contents (click to expand)

Earth’s Axial Tilt
No Night In Utqiaġvik (Formerly Barrow), Alaska For 84 Days Straight

In Utqiaġvik (the town formerly called Barrow), Alaska, the sun does not set for roughly 84 days—from around May 11 to August 2—because the town sits north of the Arctic Circle. Earth’s 23.5° axial tilt keeps the North Pole leaning toward the Sun for the entire northern summer, so any spot inside the Arctic Circle stays in continuous daylight for weeks or months. The same tilt is responsible for an equally long polar night the following winter.

We think of the length of a day as an unchanging constant. Daytime is followed by nighttime, and then the cycle repeats itself endlessly without much variation from the norm.

However, did you know there is a place on Earth where the sun doesn’t set for up to 84 days?

This means it’s daylight around the clock for nearly three months straight!

This place is none other than Alaska, the biggest, most sparsely populated state in the United States. It’s known for its diverse terrain of open spaces, forests, mountains, and abundant wildlife.

Alaska_in_United_States_(US50) — The state of Alaska (pictured in red) lies northwest of Canada. (Photo Credit: TUBS / Wikimedia Commons)

Alaska is renowned for many things, one of which is that its inhabitants experience almost three months of continuous daylight during a particular time of the year.

This raises the question: Why does this happen? Day and night result from Earth’s rotation on its axis, so why does Alaska experience this strange phenomenon? And why is it only Alaska that experiences this?

Recommended Video for you:

Midnight Sun in Alaska: Why Sun Never Sets in Alaska for Months?

Earth’s Axial Tilt

We all know that Earth rotates on its axis, but many might not know that Earth does this while leaning a bit to one side, just as the leaning tower of Pisa leans to one side. This picture will help to visualize the situation on our planet better:

This is known as Earth’s axial tilt, and it is equal to 23.5 degrees. Basically, if you were to draw a line through the north and south poles, passing through Earth’s center, the angle between this line and a line drawn perpendicular to the plane of Earth’s orbit would be 23.5 degrees.

earth

Have you ever noticed that globes are tilted? This is not done for aesthetic appeal, nor is it a manufacturing defect; globes are designed this way to genuinely illustrate Earth’s axial tilt.

Earth’s axial tilt causes the seasons. As our planet moves around the sun, the seasons are determined by where the poles are pointed with respect to our nearby star!

No Night In Utqiaġvik (Formerly Barrow), Alaska For 84 Days Straight

When the Earth’s Northern Hemisphere is tilted towards the sun, the places within 23.5 degrees of the North Pole experience 100% daylight during the summer. In other words, some places in Alaska don’t experience any nights for a long time because those places lie close to the North Pole, which is constantly exposed to the sun.

24 hours day and night cycle diagram. illustration of sun and planet earth rotating on its axis. Educational poster, scientific infographic, presentation template.

Anything within 23.5 degrees of the North Pole falls under the classification of the Arctic Circle, which is just a fancy name for the northernmost of the five major latitude lines of Earth.

Earth’s Vital Areas infographic diagram showing angle of sun rays including major latitudes equator tropic of cancer and capricorn arctic and antarctic circles for science education — Notice that the Arctic Circle lies closest to the North Pole.

The Arctic Circle is located in the Northern Hemisphere, while its counterpart in the Southern Hemisphere is known as the Antarctic Circle.

Utqiaġvik (officially renamed from Barrow in December 2016), the northernmost city in Alaska, is well above the Arctic Circle. This is why it is exposed to the sun for more than two months and doesn’t experience night during that period.

On the other hand, it also gets 100% dark in the winter because the North Pole is tilted away from the sun at that time of year.

Alaska is the most sparsely populated US state due to its abnormal day and night schedule and extreme cold temperatures. However, the state of Alaska pays residents a yearly cash dividend from its oil-revenue fund—the Alaska Permanent Fund Dividend—worth $1,000–$2,000 per resident in recent years. So, if you love nature and stargazing, Alaska could be your perfect vacation destination!

Last Updated By: Ashish Tiwari

References (click to expand)