Sully County Climate
Sully County, South Dakota
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
46.0°F
Annual Precip
21.1"
Annual Snowfall
48.8"
Extreme Heat Days
30
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
4b
Minimum winter temperature range for plant survival
2,802
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Sully County
Climate Verdict
Sully County has a cool, averaging 46.0°F annually, semi-arid conditions with only 21.1 inches of annual precipitation, occasional hot days — 30.2 per year above 90°F, moderate snowfall of 48.8 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 16.9°F. summers are warm — July averages 74.4°F. Residents experience a substantial 58°F difference between winter and summer.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Sully County closely matches the South Dakota statewide average temperature of 45.6°F.
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 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.