Marion County Climate

Marion County, Iowa

JanFebMarAprMayJunJulAugSepOctNovDec49.9°AVG °F

Avg Annual Temp

49.9°F

Annual Precip

36.9"

Annual Snowfall

Extreme Heat Days

20.1

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet
1.1"
1.4"
1.9"
3.9"
4.8"
5.5"
4.3"
4.1"
3.7"
2.9"
1.9"
1.5"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring38°61°10.6"Summer71°75°13.9"Fall39°65°8.4"Winter21°27°4.0"20°40°60°80°100°

National Comparison

Warmer than 30% of US counties
Wetter than 38% of US counties
More seasonal variation than 85% of US counties

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?
The average annual temperature in Marion County, IA is 49.9°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Marion County get?
Marion County receives an average of 36.9 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
How hot does Marion County get in summer?
The average summer temperature (June-August) in Marion County is 73.0°F. The county experiences an average of 20.1 days per year above 90°F.
How cold are winters in Marion County?
The average winter temperature (December-February) in Marion County is 24.8°F. January, typically the coldest month, averages 21.2°F.

Track your own weather in Marion County

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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.

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