Northern lights in Minnesota: tonight’s chance

The border lakes, closest to the oval

Look at a magnetic map rather than an ordinary one and the Arrowhead of Minnesota pokes up toward the auroral oval like a thumb. The geomagnetic pole sits over northern Canada, and the stretch of the border between Lake of the Woods and Lake Superior lies almost due south of it, so a town like International Falls ends up at 57.6 degrees magnetic latitude even though it is no farther north on the globe than parts of Montana. That is why its threshold, Kp 4.2, is lower than Havre's or Minot's.

The National Park Service runs Voyageurs National Park on that border, a park made mostly of water, with Rainy, Kabetogama and Namakan lakes opening wide horizons to the north. The park was certified as an International Dark Sky Park in December 2020, and the NPS keeps a page on watching the northern lights over Voyageurs. Ely and the Boundary Waters edge, at Kp 4.5, share the same advantage: very little artificial light between you and the oval.

From the North Shore down to the Mississippi bluffs

Below the border lakes, the state steps down one storm level at a time. Duluth and the North Shore need a G1 (Minor) storm; the shore runs northeast from the city, so the best views look out over Lake Superior with the dark Canadian side ahead. From Duluth through St. Cloud (Kp 5.7) to the Twin Cities, the Kp that first lifts the aurora above the horizon in this site's method is also the Kp that brings the edge of the oval overhead, so a first sighting there can fill much of the northern sky at once. The Twin Cities need Kp 5.9 and the southeast corner, around Rochester and the Mississippi bluffs, Kp 6.3. The western prairie toward Moorhead is a good surprise: almost no trees, almost no relief, and a horizon flat enough that even a low glow stays in view. The Duluth page and the Minneapolis page give the details for those two cities.

Cold, clear Arctic highs

Minnesota's weather favors the aurora in an unexpected season. When a high pressure system slides down from Canada in January or February, it brings dry, still air and some of the clearest skies of the year, which is why midwinter tops the clear dark hours in the north of the state. The price is cold well below zero Fahrenheit at night. November, by contrast, is often grey as the first cold air moves over lakes that are still open. Central time also helps: the SWPC forecast block 06 to 09 UT falls between midnight and 3 am Central Standard Time, inside the darkest part of a winter night.