Wisconsin has a humid continental climate, characterized by significant temperature variations and distinct seasons. Snowfall is a regular feature, generally spanning from mid-autumn to late spring. The state’s large north-to-south expanse and proximity to the Great Lakes create a wide range of annual snowfall totals and timing, depending greatly on location.
The Timing of First Snowfall
The first measurable snowfall (0.1 inches or more) arrives earliest in Wisconsin’s northern counties. This region, particularly near the Lake Superior shoreline, typically sees accumulation by mid to late October. This early onset relates to higher elevations and cold air passing over the warm waters of Lake Superior.
The central and southern regions generally wait until November for snow that impacts daily life. The average date for the first measurable snowfall falls within early to mid-November. Madison averages its first measurable snowfall around November 12th, and Milwaukee sees it around November 14th. While a trace of snow can occur in late October, accumulations substantial enough to affect travel usually do not happen until late November.
Peak Winter Snow Accumulation
The heart of the snow season centers on the meteorological winter months of December, January, and February. These months consistently deliver the highest monthly accumulation totals, driven by frequent large-scale winter storms. January and February are typically the coldest and snowiest, providing the most sustained accumulation.
High monthly averages underscore the peak of the winter season. Milwaukee averages 10.4 inches in December, increasing to 14.9 inches in January, and tapering to 11.8 inches in February. Madison follows a similar pattern, averaging 12.0 inches in December, 13.7 inches in January, and 12.8 inches in February.
These totals reflect frequent, smaller snowfalls combined with several major snow events each season. Persistent cold temperatures mean fallen snow is less likely to melt quickly, leading to continuous snow cover. This period sees the greatest frequency of winter weather advisories and heavy snowfalls.
Geographical Differences in Snowfall
Snowfall totals vary dramatically across Wisconsin, primarily due to the Great Lakes and local topography. The most extreme amounts fall within the Lake Superior snow belt, which can receive up to 160 inches annually. This area is heavily impacted by lake-effect snow, occurring when cold air masses move across warmer lake water, picking up moisture and depositing heavy snow downwind.
The Lake Michigan shoreline also experiences lake-effect snow, though it is less intense than the Lake Superior region. Cities like Milwaukee and Green Bay receive moderate lake enhancement, but warmer lake temperatures can sometimes delay the season’s onset compared to the far north. Inland areas of Southwestern and Central Wisconsin, removed from the Great Lakes’ influence, generally see the lowest annual snowfall. Madison’s 51.8 inches and Milwaukee’s 48.7 inches illustrate the moderate totals for these areas compared to the northern snow belts.
The End of the Snow Season
The transition out of the snow season typically begins in March, though the last measurable snowfall often occurs in April. On average, Madison and Milwaukee record their final measurable snowfall (0.1 inch or more) around April 10th and April 11th, respectively. Snow that falls during March and April often melts quickly due to increasing solar intensity and warmer daytime temperatures.
Light, non-accumulating flurries can extend into May, especially in the northern half of the state and higher elevations. A trace of snow has occasionally occurred as late as May 31st in both Milwaukee and Madison, demonstrating the potential for late-season anomalies. After mid-April, however, any remaining snow events are generally brief and temporary, signaling the end of the winter accumulation cycle.