Franklin County Climate
Franklin County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
56.1°F
Annual Precip
45.8"
Annual Snowfall
9.8"
Extreme Heat Days
39
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
4,192
Excellent for heat-loving crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Franklin County
Climate Verdict
Franklin County has a mild, with an average annual temperature of 56.1°F, moderately wet with 45.8 inches of annual precipitation, occasional hot days — 39.05 per year above 90°F, light snow averaging 9.8 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 31.6°F. summers are warm — July averages 78.2°F. The 47°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
Franklin County is 3.3°F warmer than the Illinois statewide average of 52.8°F, it is somewhat wetter than average for Illinois.
Climate Profile
About Franklin County Weather
Warm Southern Illinois Influences
Franklin County averages 56.1°F annually, making it notably warmer than the national median. This reflects a humid subtropical influence common in the southern tip of the state.
One of the State's Warmest Spots
The county's annual average of 56.1°F is over three degrees higher than the state average of 52.8°F. It consistently ranks as one of the warmest counties in Illinois.
High Precipitation in the South
At 45.8 inches of annual precipitation, Franklin is much wetter than central and northern Illinois. It shares this high-moisture profile with its neighbors in the coal belt region.
Hot Summers and Light Snow
Residents experience 39 extreme heat days reaching 90°F or higher each year. Conversely, snow is rare compared to the rest of the state, averaging only 9.8 inches annually.
Plan for High Energy Cooling
Air conditioning systems face heavy demand during the nearly 40 days of extreme heat. Light winter gear is usually sufficient, as average winter temperatures rarely drop far below freezing.
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.