Henderson County Climate
Henderson County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.9°F
Annual Precip
37.2"
Annual Snowfall
16.9"
Extreme Heat Days
21
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
3,578
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Henderson County
Climate Verdict
Henderson County has a mild, with an average annual temperature of 51.9°F, moderate rainfall of 37.2 inches per year, occasional hot days — 20.6 per year above 90°F, light snow averaging 16.9 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 24.0°F. summers are warm — July averages 76.2°F. Residents experience a substantial 52°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Henderson County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Henderson County closely matches the Illinois statewide average temperature of 52.8°F, it is somewhat drier than average for Illinois.
Climate Profile
About Henderson County Weather
A typical continental climate near national medians
At 51.9°F, Henderson County is just slightly cooler than the national median of 53°F. This area experiences the full range of four distinct seasons.
Slightly cooler than the average Illinois county
The annual temperature of 51.9°F trails the Illinois state average of 52.8°F by almost a full degree. This cooler profile is typical for the northwestern part of the state.
One of the drier counties in the region
Henderson's 37.2 inches of annual precipitation is well below the state average of 41.7 inches. It is notably drier than nearby Hancock County to the south.
Cold winters and three weeks of extreme heat
The county sees 21 extreme heat days annually and averages 16.9 inches of snow. January is cold, with an average temperature of just 24.0°F.
Prepare for cold snaps and moderate snowfall
Keep snow removal tools ready for the 16.9-inch annual average. Home insulation should be rated for the 24.0°F January lows and 76.2°F July highs.
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.