Dallas County Climate
Dallas County, Iowa
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
48.9°F
Annual Precip
36.1"
Annual Snowfall
—
Extreme Heat Days
20
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
3,139
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Dallas County
Climate Verdict
Dallas County has a cool, averaging 48.9°F annually, moderate rainfall of 36.1 inches per year, occasional hot days — 20.2 per year above 90°F. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 19.8°F. summers are warm — July averages 74.5°F. Residents experience a substantial 55°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Dallas County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Dallas County closely matches the Iowa statewide average temperature of 48.0°F.
Climate Profile
About Dallas County Weather
A Classic Midwestern Continental Climate
Dallas County maintains an average annual temperature of 48.9°F, which sits below the national median for U.S. counties. This humid continental climate experiences distinct seasonal shifts and reliable precipitation, averaging 36.1 inches annually. Residents navigate a landscape that is notably cooler than the more temperate regions of the American South.
Warmer Than the Iowa Average
With an annual average of 48.9°F, Dallas County is nearly a full degree warmer than the statewide average of 48.0°F. While much of Iowa faces harsher northern winds, this central county enjoys a slightly more moderate thermal profile. It aligns perfectly with the state's average precipitation of 36.1 inches, supporting the region's productive agricultural roots.
Balanced Weather in Central Iowa
Dallas County's 48.9°F average temperature makes it warmer than northern neighbors like Dickinson, which sits at 45.9°F. It provides a middle ground between the colder northern tier and the warmer southern counties like Davis. This positioning results in a climate that avoids the extreme cold of the border while maintaining manageable summer peaks.
Sharp Seasonal Swings and Summer Heat
Summers in Dallas County are intense, with an average of 20 days per year reaching or exceeding 90°F. Winter brings a significant chill as the January average drops to 19.8°F and the seasonal average hovers at 23.2°F. While specific local snowfall data is unavailable, the county's winter profile suggests consistent frozen precipitation throughout the season.
Prepare for High-Efficiency Living
The 20 days of extreme heat require robust HVAC systems to handle the 74.5°F July average. Since winter temperatures frequently drop below 20°F in January, high-quality home insulation and heavy-duty winter gear are essential for local comfort. Residents should plan for a wide range of outdoor conditions given the county's nearly 55-degree spread between winter and summer lows.
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.