Sullivan County Climate
Sullivan County, Missouri
Avg Annual Temp
49.8°F
Annual Precip
40.3"
Annual Snowfall
17.0"
Extreme Heat Days
25.2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Sullivan County Weather
A Chilly Outlier in the Midwest
Sullivan County averages 49.8°F annually, making it notably cooler than the national median temperature. This northern Missouri climate stays well below the 54.9°F state average.
Cooler Than the Missouri Average
The county ranks among the cooler regions in the state. Its 49.8°F annual average sits over five degrees lower than the Missouri mean of 54.9°F.
Dry and Brisk Northern Borders
Sullivan receives 40.3 inches of annual precipitation, which is drier than the state average of 43.8 inches. It experiences 25 extreme heat days, far fewer than counties in the southern Ozarks.
Icy Winters and Mild Summers
Winters are significant with 17.0 inches of annual snowfall and a January average of 22.4°F. Summer peaks in July at 74.0°F, offering a break from the intense heat found elsewhere.
Prepare for Snow and Cold
Residents should invest in heavy winter gear and snow removal tools to handle the 17.0 inches of yearly snow. Home heating systems must be robust to manage the 25.8°F winter average.
Frequently Asked Questions
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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.