Day County Climate
Day County, South Dakota
Avg Annual Temp
43.7°F
Annual Precip
24.1"
Annual Snowfall
40.1"
Extreme Heat Days
7.933333333333334
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Day County Weather
A Cool Northern Continental Climate
Day County's 43.7°F average temperature is significantly cooler than the national median. This northern location brings sharp seasonal transitions and long, cold winters.
Chillier than the State Average
The county stays nearly 2 degrees cooler than the South Dakota average of 45.6°F. This makes it one of the state's chillier jurisdictions, particularly during the deep winter months.
Higher Precipitation than Western Peers
At 24.1 inches of annual precipitation, Day County is wetter than the state average of 22.7 inches. This extra moisture often translates to 40.1 inches of snow during the long winter season.
Mild Summers and Frigid Winters
January averages a frigid 12.3°F while July reaches a comfortable 71.5°F. The area only sees 8 days of 90-degree heat, offering a significant reprieve from the summer intensity felt elsewhere in the state.
Focus on Winter Readiness
High-quality winter gear is a priority here given the 15.8°F winter average and consistent snow accumulation. Residents enjoy lower summer cooling costs but must invest heavily in home insulation and heating reliability.
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.