Sully County Climate
Sully County, South Dakota
Avg Annual Temp
46.0°F
Annual Precip
21.1"
Annual Snowfall
48.8"
Extreme Heat Days
30.2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Sully County Weather
Typical Interior Plains Temperature Trends
Sully County averages 46.0°F per year, trailing the national median temperature. This highlights a climate of extremes typical of the North American interior.
Matching the South Dakota Baseline
The county's 46.0°F average nearly matches the state average of 45.6°F. Its 21.1 inches of precipitation also aligns closely with the state's overall average of 22.7 inches.
Heavy Snow Compared to Neighbors
Sully faces a significant 48.8 inches of snow annually, far outstripping the 31.3 inches seen in neighboring Stanley County. This makes it one of the snowier regions in central South Dakota.
Cold Winters and Frequent Heat
January temperatures average a cold 16.9°F, but summers heat up quickly with 30 days per year over 90°F. The seasonal swing is dramatic, moving from a 19.5°F winter to a 71.3°F summer average.
Equip for Serious Snow Removal
Homeowners need heavy-duty snow removal equipment to manage nearly 50 inches of annual accumulation. HVAC systems must be robust enough to bridge the wide gap between deep freezes and summer heat.
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.