Clinton County Climate
Clinton County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
55.7°F
Annual Precip
42.9"
Annual Snowfall
10.1"
Extreme Heat Days
32
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6b
Minimum winter temperature range for plant survival
4,186
Excellent for heat-loving crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Clinton County
Climate Verdict
Clinton County has a mild, with an average annual temperature of 55.7°F, moderately wet with 42.9 inches of annual precipitation, occasional hot days — 31.6 per year above 90°F, light snow averaging 10.1 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 78.2°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
Clinton County closely matches the Illinois statewide average temperature of 52.8°F.
Climate Profile
About Clinton County Weather
A warm, wet climate above national averages
Clinton County’s 55.7°F average temperature is significantly higher than the national median, indicating a warmer-than-average climate. Its 42.9 inches of rain also surpasses the typical precipitation seen across many U.S. counties.
Nearly three degrees warmer than the state average
As one of the warmest counties in Illinois, Clinton’s 55.7°F average is nearly three degrees higher than the state average. This warmth is a defining characteristic of its location in the southwestern part of the state.
High July heat compared to eastern neighbors
Clinton is warmer than Clark County to the northeast, and it experiences slightly less snowfall at 10.1 inches. While it has 32 extreme heat days, this is actually fewer than the 40 days recorded in neighboring Clay County.
Sizzling July peaks and light snowfall
July is particularly hot with an average of 78.2°F, the highest in this eight-county set. Winter is relatively short and mild, with temperatures averaging 33.3°F and very little snow accumulation.
Focus on high-capacity cooling for July
The high July temperatures of 78.2°F make reliable air conditioning a necessity for all households. Minimal snowfall of 10.1 inches means heavy winter equipment is rarely needed, though basic ice prep remains important.
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.