Mellette County Climate
Mellette County, South Dakota
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
48.1°F
Annual Precip
20.4"
Annual Snowfall
45.1"
Extreme Heat Days
39
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5a
Minimum winter temperature range for plant survival
2,926
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Mellette County
Climate Verdict
Mellette County has a cool, averaging 48.1°F annually, semi-arid conditions with only 20.4 inches of annual precipitation, occasional hot days — 39.25 per year above 90°F, moderate snowfall of 45.1 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 23.1°F. summers are warm — July averages 74.7°F. Residents experience a substantial 52°F difference between winter and summer.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Mellette County closely matches the South Dakota statewide average temperature of 45.6°F, it is somewhat drier than average for South Dakota, the county experiences 15.720303418803422 more extreme heat days than the state average.
Climate Profile
About Mellette County Weather
One of the Region's Warmest Spots
Mellette County averages 48.1°F annually, which is notably warmer than its South Dakota peers. However, it remains below the national median temperature due to its northern latitude. The local climate is marked by significant extreme heat and moderate total precipitation.
A State Leader in Extreme Heat
With 39 days of extreme heat over 90°F, Mellette County is much hotter in the summer than the South Dakota average. Its annual temperature of 48.1°F is also well above the state average of 45.6°F. Precipitation levels are slightly lower than the state norm, totaling 20.4 inches.
Topping the Region in Snow and Sun
Mellette County is an outlier with its high count of 39 heat days and its significant 45.1 inches of snowfall. It experiences more extreme heat than almost all its neighbors while maintaining heavy winter totals. This volatility makes it one of the more climate-stressed counties in the state.
Intense Summer Sun and Snowy Winters
Summer in Mellette is hot, with a July average of 74.7°F and over five weeks of 90°F days. Winters are equally intense, averaging 25.0°F from December to February with over 45 inches of snow. The transition from intense heat to heavy snow requires significant resilience from local infrastructure.
Resilience Against Heat and Drifts
Robust air conditioning is critical to handle the 39 days of extreme heat each summer. Simultaneously, residents need high-performance winter gear to manage 45.1 inches of snow and January lows of 23.1°F. Home maintenance should focus on both heat reflection and heavy-duty winter insulation.
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.