Wisconsin has a continental climate. Summers are warm and winters very cold, especially in the upper northeast and north-central lowlands, where the freeze-free (growing) season is around 80 days. The average annual temperature ranges from 39°F (4°C) in the north to about 50°F (10°C) in the south. At Danbury, in the northwest, the average January daily temperature over a 34-year period was 8°F (–13°C), and the average July daily temperature 68°F (20°C); at Racine, in the southeast, these figures were 21°F (–6°C) and 72°F (22°C), respectively. Over a 30-year period ending in 1990, Milwaukee had average daily temperatures ranging from 12°F (–11°C) to 26°F (–3°C) in January and from 62°F (17°C) to 80°F (27°C) in July. Among major US metropolitan areas, only Minneapolis-St. Paul is colder than Milwaukee. The lowest temperature ever recorded in Wisconsin was –55°F (–48.3°C), at Couderay on 4 February 1996; the highest, 114°F (46°C), at Wisconsin Dells on 13 July 1936.

Annual precipitation in the state ranges from about 34 in (86 cm) for parts of the northwest to about 28 in (71 cm) in the south-central region and the areas bordering Lake Superior and Lake Michigan. In Milwaukee average annual precipitation (1971–2000) was is 34.8 in (88.4 cm); April, June, and July are the rainiest months in Milwaukee. Milwaukee's annual snowfall averages 47 in (119 cm); the average wind speed is 12 mph (19 km/hr).