Marion County Climate
Marion County, Iowa
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
49.9°F
Annual Precip
36.9"
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
3,279
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Marion County
Climate Verdict
Marion County has a cool, averaging 49.9°F annually, moderate rainfall of 36.9 inches per year, occasional hot days — 20.1 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 21.2°F. summers are warm — July averages 75.1°F. Residents experience a substantial 54°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Marion County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Marion County closely matches the Iowa statewide average temperature of 48.0°F.
Climate Profile
About Marion County Weather
A warm pocket in the Midwest
Marion County averages 49.9°F annually, which is on the higher end for Iowa but remains below the national median. The area experiences a robust humid continental climate with frequent summer heatwaves.
Leading the state in heat
Marion's 49.9°F average is nearly two degrees higher than the Iowa state average. It also sees 20 days of extreme heat annually, which is significantly higher than many northern counties.
More extreme heat than neighbors
Marion records 20 days above 90°F, surpassing neighbors like Mahaska and Madison. While its temperature is high, its 36.9 inches of rain is very close to the state average.
Intense summers and cold winters
Summer is a major factor here, with a July average of 75.1°F. Although specific snowfall totals are currently unlisted, winter temperatures average 24.8°F, providing a sharp contrast to the summer heat.
Prioritize high-efficiency cooling
With 20 days of extreme heat, a robust cooling system is essential for resident safety and comfort. Homeowners should also prepare for a 21.2°F January, the coldest month of the year.
Frequently Asked Questions
What is the average temperature in Marion County?
How much rain does Marion County get?
How hot does Marion County get in summer?
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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.