Mundelein, IL Climate

Climate Insight: Mundelein, IL

Based on station USC00115961 feeding NOAA's 1991–2020 climate normals, Mundelein, Illinois averages 48°F a year, ranging from a mean daily high of 57°F to a mean daily low of 39°F. July is typically the warmest month of the year, while January is the coldest. Because these figures are thirty-year averages rather than any single year's readings, they describe the typical month, not a forecast for it.

Rainfall (and snow, where it falls) shapes day-to-day life here as much as temperature does. Mundelein sees about 38.5 inches of precipitation a year, with 43.1 inches typically falling as snow. The frost-free season averages 174 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 29 and the first fall freeze near October 20. On the energy side, 6,875 heating degree days and 693 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Mundelein scores 59/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows, shoulder seasons for mild highs and lows, peak summer for July-driven heat, or deep winter for January-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.