Greene County Climate
Greene County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
52.9°F
Annual Precip
40.3"
Annual Snowfall
17.9"
Extreme Heat Days
25
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
3,639
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Greene County
Climate Verdict
Greene County has a mild, with an average annual temperature of 52.9°F, moderately wet with 40.3 inches of annual precipitation, occasional hot days — 24.7 per year above 90°F, light snow averaging 17.9 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 26.9°F. summers are warm — July averages 75.7°F. The 49°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Greene County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Greene County closely matches the Illinois statewide average temperature of 52.8°F.
Climate Profile
About Greene County Weather
Typical Mid-American Climate
Greene County’s 52.9°F annual average temperature aligns perfectly with the national median. It offers a balanced climate typical of the American heartland.
Mirroring the Illinois Average
The county's 52.9°F average temperature is nearly identical to the Illinois state average of 52.8°F. It serves as a climate bellwether for the entire state.
Drier Than Southern Neighbors
Receiving 40.3 inches of annual precipitation, Greene is slightly drier than the Illinois average of 41.7 inches. This makes it a transition point between the wet south and drier north.
Steady Heat and Moderate Snow
The county sees 25 extreme heat days annually where temperatures hit 90°F. Winters bring a manageable 17.9 inches of snow, with January averages staying around 26.9°F.
Prepare for Seasonal Extremes
A dual-purpose HVAC system is necessary to handle both the 25 heat days and the sub-freezing winter nights. Keep snow removal tools ready for the nearly 18 inches of expected snowfall.
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.