Sullivan County Climate
Sullivan County, Indiana
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
54.5°F
Annual Precip
45.6"
Annual Snowfall
15.1"
Extreme Heat Days
23
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6b
Minimum winter temperature range for plant survival
3,878
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Sullivan County
Climate Verdict
Sullivan County has a mild, with an average annual temperature of 54.5°F, moderately wet with 45.6 inches of annual precipitation, occasional hot days — 23.35 per year above 90°F, light snow averaging 15.1 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 29.4°F. summers are warm — July averages 76.3°F. The 47°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Sullivan County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Sullivan County closely matches the Indiana statewide average temperature of 52.4°F.
Climate Profile
About Sullivan County Weather
Sullivan County's Temperate Balance
The county maintains an annual average of 54.5°F, which is warmer than the national median. It experiences a robust four-season climate typical of the Ohio Valley.
Exceeding the State Temperature Average
Sullivan's 54.5°F average is over two degrees higher than the Indiana state average of 52.2°F. It is part of the warmer southwestern quadrant of the state.
Matching the Southern Indiana Gradient
Sullivan mirrors the climate of Scott County almost exactly. It is significantly warmer and less snowy than northern counties like St. Joseph.
Hot July Peaks and Moderate Snow
July averages 76.3°F with 23 days of extreme heat above 90°F. Winters are manageable with 15.1 inches of snow and a January average of 29.4°F.
Balance Your Seasonal Home Prep
Ensure your HVAC system is ready for 23 days of extreme heat and 15 inches of winter snow. Check your home's drainage to handle the 45.6 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.