Climatic Conditions : Michigan

Michigan enjoys a temperate climate with well-defined seasons. The southern part of the lower peninsula experiences the warmest temperatures and longest frost-free periods. Detroit has a normal daily mean temperature of 49°F (9°C), ranging from 23°F (–5°C) in January to 72°F (22°C) in July. Marie has a normal daily mean of 40°F (4°C), ranging from 13°F (–11°C) in January to 64°F (18°C) in July. The coldest temperature ever recorded in the state is –51°F (–46°C), registered at Vanderbilt on 9 February 1934; the all-time high of 112°F (44°C) was recorded at Mio on 13 July 1936.

Areas in the extreme northern region receive maximum snowfall. Houghton and Calumet, on the Keweenaw Peninsula, average 183 in (465 cm) of snow a year, more than any other area in the state. Similarly, Lake Michigan's water temperatures create a snow belt along the west coast of the lower peninsula.

Cloudy days are more common in Michigan than in most states. Michigan receives sunshine for only 49% of the year. The annual average relative humidity at Detroit is 81% at 7 AM, dropping to 60% at 1 PM; at Sault Ste. Marie, the comparable percentages are 85% and 67%, respectively. Late spring and early summer are the peak of the tornado season.