Northern Lights Forecast Tonight — Whitehorse, Yukon

The Kp index is the most widely used measure of global geomagnetic activity. It runs from 0 (quiet) to 9 (extreme storm). In Whitehorse, which sits directly under the auroral oval, a Kp of 1 or 2 is often enough for a beautiful aurora on a clear night. A Kp of 4 or above typically produces active curtains visible to the naked eye. A Kp of 6 or above can light up the entire sky. The index is updated every three hours by NOAA — check it early in the evening and again around 9 pm.

Cloud cover is the single most important factor — and often the most frustrating one. Even a major geomagnetic storm is invisible behind a thick cloud layer. We monitor several weather models simultaneously and, when necessary, drive until we find clear sky — sometimes 100 km or more from Whitehorse.

Dark hours matter as much as solar activity. Aurora season in Whitehorse runs from late August through late March, when nights are long and dark enough. Aurora activity peaks around local magnetic midnight, which is roughly 11:30 pm local time. Getting out to a dark site before 10 pm gives you the best viewing window.