The climate throughout Wisconsin is a typical continental humid climate, which means warm humid summers and cold snowy winters. The southern region of the state is slightly warmer than the northern parts around the Great Lakes. The lakes create their own microclimate that brings significantly more snow during winter and colder temperatures in general.
Few places in Wisconsin get much hotter than the upper 80s°F during the peak of summer between June and August. Thunderstorms are common most weeks, with the occasional heat spell that pushes the mercury into the 90s°F. While summers are usually very nice here, the humidity levels get pretty high, creating plenty of stuffy sweaty days in summer. September is a great month in terms of weather, with highs in the 70s (°F) and less precipitation. October gets even better as the hardwood trees turn color and the weather cools off nicely.
Winter is the rough season in Wisconsin. Between December and February the daytime highs rarely top 30°F, and night lows dip well below freezing. Wisconsin gets a lot of snow, with an average of 40 inches in the south and up to 160 inches in the north within the Lake Superior snowbelt. Travelers who like white snowy weather will be very pleased with Wisconsin in January. Spring is a mixed bag, with frequent rain but plenty of beautiful weather as well. By May the temperatures are back to the mid-60s (°F).
Best Time to Visit Wisconsin
Unless you are coming for cross country skiing, snowmobiling, or snowshoeing, Wisconsin’s best weather is usually in the fall. Between September and early November the temperatures drop gradually from the 70s (°F) to the upper 50s (°F) by early November. The leaves are a major highlight throughout the state, usually peaking in color by the middle of October. Summer is also a very busy time because the long winters make everyone giddy to get outside while they can.
Expect the most crowds between late June and the end of August. Wisconsin rarely feels uncomfortably crowded, even at the height of summer. If you are looking for good deals of lodging consider a visit in the spring months of April or May. The weather is often beautiful and nobody is really out and about yet.