Aurora Borealis in Alaska

The aurora borealis, or northern lights, is a natural light display caused when charged particles from the Sun strike gases in Earth’s upper atmosphere. Alaska is considered one of the best places in the world to see it, and Fairbanks sits almost directly beneath the auroral oval. The aurora season runs from late August through early April, with peak viewing from November through February [1][2].

How the Aurora Forms

The northern lights begin on the Sun, which constantly emits the solar wind, a stream of charged particles, mainly electrons and protons. Solar flares and coronal mass ejections can send large plasma bursts toward Earth. Earth’s magnetosphere deflects most of the solar wind, but near the poles magnetic field lines dip toward the surface and let particles enter the upper atmosphere, where they collide with oxygen and nitrogen atoms at roughly 60 to 200 miles up [2].

Colors

Oxygen around 60 miles up produces a green-yellow glow, the most common color. Oxygen around 200 miles up glows red, and nitrogen produces blues and purples [2].

The Auroral Oval

The auroral oval is a ring around the magnetic poles where auroras appear most often, shaped like a skewed doughnut centered on the geomagnetic North Pole. Alaska is probably the best place in the world to see the aurora, and Fort Yukon may be the aurora capital of the world based on statistics [1]. Fairbanks sits almost directly beneath the oval, so visitors look up rather than toward the horizon [2].

Seasons and Timing

The aurora happens all year, but long summer daylight makes the sky too bright to see it. The season runs from late August through early April, with peak viewing from November through February and heightened activity near the equinoxes in September and March [2]. According to the Geophysical Institute, the best chance to see bright arcs is usually between about 11 p.m. and 1 a.m. [1].

Viewing Geometry

The lower edge of an auroral arc is about 80 kilometers up, so Fairbanks residents can see displays over Fort Yukon, and an aurora directly overhead at Fort Yukon would appear about 20 degrees above the northern horizon from Fairbanks [1].

Forecasting

The Kp index runs from 0 to 9 and is updated every three hours by NOAA’s Space Weather Prediction Center. At Kp 2 or 3 the aurora can be visible in Alaska, especially Fairbanks. At Kp 5 and above, displays are dramatic and visible across most of the state, and at Kp 7 or higher they may fill the sky and be visible in southern Alaska. Clouds can block a display even when the Kp index is high [2].

Solar Cycle

Solar Cycle 25 peaked in late 2024, and elevated activity was expected through at least 2026 [2]. See the entries on the midnight sun and polar night in Alaska, Interior Alaska and tourism in Alaska.

FAQs

What causes the northern lights? Solar wind particles colliding with oxygen and nitrogen in the upper atmosphere.

When is the best time to see the aurora in Alaska? Late August to early April, with peak viewing from November through February.

Why is Fairbanks good for viewing? It sits almost directly beneath the auroral oval.

What color is the aurora? Mostly green-yellow, with red from high oxygen and blue or purple from nitrogen.

What does the Kp index measure? Geomagnetic activity on a 0–9 scale, used to forecast aurora.

Sources

1. Geophysical Institute, University of Alaska Fairbanks: Aurora season
2. Alaska Travel: The Science Behind Alaska’s Northern Lights

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 12, 2026Researched and drafted with AI assistanceReport an issue