Northern lights in Wisconsin: tonight’s chance

Bayfield, the Apostle Islands and the north coast

Wisconsin's best aurora ground is its short Lake Superior coast, which faces north across open water toward Ontario. The Bayfield Peninsula pushes out into the lake there, and the National Park Service manages the Apostle Islands National Lakeshore at its northern tip: 21 islands and a stretch of mainland shoreline with very little light. Ashland, at the head of Chequamegon Bay, and Superior, across the harbor from Duluth, both need about Kp 5.1, which puts the north coast within reach of a G1 (Minor) storm on a clear night. The same shore also brings lake cloud in early winter, which is why December is the greyest month there.

The Northwoods, the middle and the south

Below the Superior coast the state is a long slope of rising thresholds. The Northwoods lake country, with its scattered small lakes and few towns, sits between the coast and Wausau, which needs Kp 5.9. The center of the state, around Eau Claire and Stevens Point, needs about Kp 6.0, and the south needs Kp 6.5. Between the coast and Milwaukee the threshold rises by about 1.4 Kp, a full step on the storm scale. The southwest corner, the hilly Driftless Area along the Mississippi, is dark but deeply cut by valleys: watch from a ridge top, not from a coulee bottom.

Wisconsin's eastern shore faces the wrong way

Lake Michigan gives eastern Wisconsin its most open horizons, but they point east. From Milwaukee, Sheboygan or Manitowoc, the lake covers the northeast at best, and the north runs up a lit shoreline. Green Bay is a partial exception: the bay itself reaches northeast from the city, and the Door Peninsula offers dark shores with water to the north and east. Inland, the flat farmland of the Fox Valley often gives a cleaner northern view than the coast. The pages for Milwaukee, Madison and Green Bay go into each city, and the Minnesota page covers the other side of the St. Croix.