Alaska aurora season runs September to March. Fairbanks, 200 miles north of Anchorage at 64.8°N latitude, sits directly under the auroral oval, and its geomagnetic corridor plus dark-sky access make it the highest-probability aurora base in the state. If you are booking a dedicated aurora trip, book Fairbanks or Chena Hot Springs, not Anchorage.
Best months
Late August to mid-April is technically aurora season in Fairbanks. Late September through March is the practical window (August still has too much daylight, April aurora exists but the season winds down fast). March around the vernal equinox is often the strongest month; the equinox correlates with heightened geomagnetic activity. December and January are dark and cold, which helps.
KP index basics
The KP index (0 to 9) is the widely-used measure of geomagnetic activity. Fairbanks needs a KP of only 1 or 2 for aurora directly overhead. Anchorage typically needs KP 4 to 5. Utqiagvik and the Brooks Range needs practically nothing. Check the Geophysical Institute Aurora Forecast (auroraforecast.gi.alaska.edu). No forecast is more than roughly 60% reliable more than a few days out.
Where to stay
Aurora-purpose-built lodges (Chena Hot Springs Resort, Borealis Basecamp, Aurora Villa, Aurora Pointe) are the practical answer for most travellers. All have dark-sky access, wake-up service when the aurora fires, and either a heated viewing yurt, bubble dome, or observation pad. See our 10 best aurora hotels roundup for detailed picks.