Temperatures and Precipitation

Statewide summer (June–Aug.) and winter (Dec.–Feb.) mean temperatures are 67 and 11 degrees respectively, though the north and south differ by as much as 15 degrees. You never know exactly what you will get during the autumn. Duluth, for instance, has seen 37 inches of snow during a Halloween storm, but also a Thanksgiving high of 66 degrees.

Minnesota’s record high temperature is 115°F (July 29, 1917, Beardsley), beating out such notorious hot spots as Atlanta (105°), Los Angeles (112°), and El Paso (114°). The all-time low is 60 below zero (Feb. 2, 1996, near Tower).

While temperatures are warmest in the southwest corner and coolest in the northeast, precipitation runs contrary, increasing from about 18 inches in the northwest to 32 inches in the southeast. Most falls during the May to September growing season.

Total annual snowfall is around 40 inches in the south and over 60 inches in the north. There is at least one inch of snow on the ground an average of 160 days in the northeast and 85 days in the southwest. In an average year, Minnesota sees about 16 snowstorms with an inch or more of accumulation, though usually only one of those is a full-on blizzard.

While an inch or two of snow will slow down travel a bit, a winter storm doesn’t become a real nuisance to Minnesotans until about six inches have fallen.

Lake Effect

Lake Superior is so big that it creates its own weather. With an average annual temperature of just 39 degrees, Superior cools the surrounding air in the summer and warms it in the winter, moderating the climate by as much as 15 degrees over inland temperatures. The effect does not extend very far because it is blocked by the Sawtooth Range and pushed back by winds that normally blow out of the west. Some of Minnesota’s larger inland lakes have a similar but smaller effect in the summer.

Lake Superior also creates its own snowstorms. When moist air blows inland from the east and up the hills lining the North Shore, it condenses and falls as snow, making the North Shore the snowiest part of the state by far.

© Tim Bewer from Moon Minnesota, 3rd Edition