About & method

Alaska Aurora Forecast answers one question for 34 Alaska communities: can I see the northern lights tonight? Every town gets a plain-word verdict — Excellent, Good, Fair, or Poor — not a raw index you have to interpret yourself.

How a verdict is made

Four ingredients, all checked for the town's own dark hours:

Geomagnetic activity. NOAA's Space Weather Prediction Center (SWPC) publishes a 3-day Kp forecast in 3-hour blocks. Each town needs a different Kp, set by its magnetic latitude: the auroral oval's southern edge sits near magnetic latitude 69 − 3×Kp at midnight, so Fairbanks (magnetic latitude ~65°) needs only about Kp 2, Anchorage about 3, Ketchikan about 4.

The band on the globe is drawn from that same law for tonight's forecast peak, and the page also reads NOAA's live OVATION model grid (updated about every 5 minutes, looking 30–90 minutes ahead) for the "aurora right now" line in each town's record.

Cloud cover. The spoiler most aurora sites ignore. We pull the National Weather Service cloud-cover forecast for each town's dark hours; solid overcast vetoes the night no matter how strong the aurora is, and partial cloud steps the verdict down.

Darkness and moonlight. A town's true-dark window (astronomical dusk to dawn) is computed with the standard NOAA solar algorithm — the same math as our sister site Alaska Daylight. In midsummer most of Alaska never gets truly dark, and the site says so instead of pretending. Moon illumination is computed from the lunar cycle and shown with every call.

Honest limits

Aurora forecasting is part science, part luck. Kp is a 3-hour planetary average; the OVATION model is driven by solar wind measured about a million miles upstream. A "Good" night can bust and a "Fair" one can surprise you. Treat verdicts as odds, not promises — and if the sky is clear and you're already up, look north anyway.

Data sources

NOAA SWPC (OVATION grid, Kp forecast, 27-day outlook), National Weather Service (cloud cover). All feeds are free public data; all times on this site are Alaska Time.

Sister sites

Alaska Daylight — sunrise, sunset, and daylight hours for every Alaska town. Alaska Tide Charts — tide predictions for 524 Alaska stations.