Sullivan County Climate

Sullivan County, Indiana

JanFebMarAprMayJunJulAugSepOctNovDec54.5°AVG °F

Avg Annual Temp

54.5°F

Annual Precip

45.6"

Annual Snowfall

15.1"

Extreme Heat Days

23.35

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.2"
2.5"
3.5"
4.8"
4.9"
4.9"
4.5"
3.2"
3.3"
3.9"
3.8"
3.0"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring43°65°13.2"Summer73°76°12.6"Fall44°68°11.1"Winter29°34°8.7"20°40°60°80°100°

National Comparison

Warmer than 49% of US counties
Wetter than 58% of US counties
More seasonal variation than 63% of US counties

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

What is the average temperature in Sullivan County?
The average annual temperature in Sullivan County, IN is 54.5°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Sullivan County get?
Sullivan County receives an average of 45.6 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Sullivan County?
Yes, Sullivan County receives an average of 15.1 inches of snowfall per year according to NOAA climate normals.
How hot does Sullivan County get in summer?
The average summer temperature (June-August) in Sullivan County is 74.8°F. The county experiences an average of 23.35 days per year above 90°F.
How cold are winters in Sullivan County?
The average winter temperature (December-February) in Sullivan County is 32.4°F. January, typically the coldest month, averages 29.4°F.

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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.

Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

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