Madison County Climate
Madison County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
55.7°F
Annual Precip
44.1"
Annual Snowfall
10.5"
Extreme Heat Days
29
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
4,168
Excellent for heat-loving crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Madison County
Climate Verdict
Madison County has a mild, with an average annual temperature of 55.7°F, moderately wet with 44.1 inches of annual precipitation, occasional hot days — 29.4 per year above 90°F, light snow averaging 10.5 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 30.3°F. summers are warm — July averages 78.3°F. The 48°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
The moderate temperatures support hiking, cycling, and camping comfortably in spring, summer, and fall.
Regional Context
Madison County closely matches the Illinois statewide average temperature of 52.8°F, it is somewhat wetter than average for Illinois.
Climate Profile
About Madison County Weather
Warm Regional Climate Center
Madison County features a 55.7°F annual average temperature, placing it among the warmer counties in the Midwest. Its 44.1 inches of rainfall are well above the national median for inland counties.
Exceeding State Temperature Norms
At 55.7°F, Madison County is significantly warmer than the Illinois statewide average of 52.8°F. Its July average of 78.3°F makes it one of the hottest regions in the state.
Low Snowfall Compared to Peers
Madison averages only 10.5 inches of snow, which is much lower than the 20+ inches seen in central Illinois. It shares a high precipitation profile with southern neighbor Marion, both exceeding 44 inches of rain.
Intense Summer Heat Peaks
July is very hot here, averaging 78.3°F with 29 days of extreme heat above 90°F. Conversely, winter is the mildest of this group, with a December-February average of 33.4°F.
Investment in Summer Comfort
With nearly 30 days of extreme heat, powerful air conditioning is a primary requirement for residents. Minimal snow gear is needed, but high-quality rain protection is vital for the 44.1 inches of annual precipitation.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.