Dewey County Climate
Dewey County, South Dakota
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
45.3°F
Annual Precip
19.3"
Annual Snowfall
39.0"
Extreme Heat Days
24
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
4b
Minimum winter temperature range for plant survival
2,619
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Dewey County
Climate Verdict
Dewey County has a cool, averaging 45.3°F annually, semi-arid conditions with only 19.3 inches of annual precipitation, occasional hot days — 24.3 per year above 90°F, moderate snowfall of 39.0 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 72.7°F. Residents experience a substantial 56°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Dewey County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Dewey County closely matches the South Dakota statewide average temperature of 45.6°F, it is somewhat drier than average for South Dakota.
Climate Profile
About Dewey County Weather
Dry Air and Wide Temperature Swings
Dewey County averages 45.3°F annually, falling short of the national median but following the regional trend. This semi-arid climate features lower humidity and significant variation between day and night.
Tracking with the State Average
The county tracks very closely with the South Dakota average of 45.6°F. It represents the typical thermal experience for the central part of the state throughout the year.
Drier than Average Conditions
With 19.3 inches of annual precipitation, Dewey is drier than the state average of 22.7 inches. This dry air allows for 24 days of 90-degree heat while keeping snowfall to a modest 39.0 inches.
Hot Summers and Cold Winters
The seasons fluctuate from a July average of 72.7°F down to a January average of 16.9°F. Summer days are frequently hot, but the low 19.5°F winter average ensures a true northern winter experience.
Landscaping for a Semi-Arid Zone
Practical planning involves drought-resistant landscaping and efficient cooling for the 24 days of extreme summer heat. Winter preparations should focus on wind protection, as the open landscape offers little buffer from the cold.
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.