Sullivan County Climate
Sullivan County, Missouri
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
49.8°F
Annual Precip
40.3"
Annual Snowfall
17.0"
Extreme Heat Days
25
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
3,140
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 cool, averaging 49.8°F annually, moderately wet with 40.3 inches of annual precipitation, occasional hot days — 25.2 per year above 90°F, light snow averaging 17.0 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 22.4°F. summers are warm — July averages 74.0°F. Residents experience a substantial 52°F difference between winter and summer.
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 is 5.1°F cooler than the Missouri statewide average of 54.9°F, it is somewhat drier than average for Missouri.
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 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.