Weather

Lake Superior, with an average annual temperature of 45° F, moderates the climate, making winters warmer and summers cooler. The effect is strongest when the wind blows off the water, and is most pronounced on the shore and on slopes that face the lake.

image Courtesy of Andrew Slade

Between late spring and late fall, the shore can be shrouded in fog when inland areas bask in sunshine. These warm-season fogs occur when moisture in the warm air condenses as it flows over the cold lake. Duluth gets an average of 52 days of heavy fog each year (the Twin Cities average 11 foggy days per year). These foggy days, punctuated with the sounds of gulls and foghorns, have a powerful appeal.

Fall is the season for “northeasters.” These gales, with strong winds and rain, occur when low-pressure systems pass over the lake. Most of Lake Superior's 350 shipwrecks occurred during such storms.

In winter, temperatures near the lake rarely dip below -30° F. Inland temperatures, on the other hand, can reach -45°F.

During most winters, Lake Superior becomes 40 to 95 percent covered by ice. It occasionally freezes over completely. Open water often persists in the center of the lake because the ice that forms there is blown or broken by strong winds.

From Superior Pursuit, The University of Minnesota Sea Grant Program, republished with permission

For more information, request the publication,  North Shore Weather Wisdom from Minnesota Sea Grant.

Current Conditions

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