weatherbycounty

Mills County Climate

JanFebMarAprMayJunJulAugSepOctNovDec50.9°AVG °F

Avg Annual Temp

50.9°F

Annual Precip

34.8"

Annual Snowfall

21.6"

Extreme Heat Days

34

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
0.7"
0.9"
2.1"
3.5"
5.0"
5.5"
4.3"
4.0"
3.6"
2.6"
1.4"
1.2"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

5b

Minimum winter temperature range for plant survival

Growing Degree Days

3,476

Supports most vegetables & fruits

Last spring frost (32°F): 04/23
First fall frost (32°F): 10/11

Seasonal Overview

Comfort ZoneSpring40°62°10.6"Summer72°76°13.9"Fall39°66°7.6"Winter23°28°2.8"20°40°60°80°100°

National Comparison

Warmer than 34% of US counties
Wetter than 34% of US counties
More seasonal variation than 89% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Mills County

Climate Verdict

Mills County has a mild, with an average annual temperature of 50.9°F, moderate rainfall of 34.8 inches per year, occasional hot days — 34.1 per year above 90°F, moderate snowfall of 21.6 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 22.6°F. summers are warm — July averages 75.8°F. Residents experience a substantial 53°F difference between winter and summer.

Outdoor & Gardening Guidance

Growing season and gardening data is currently limited for Mills County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.

Regional Context

Mills County closely matches the Iowa statewide average temperature of 48.0°F, the county experiences 18.158754208754214 more extreme heat days than the state average.

Climate Profile

About Mills County Weather

A Warm Slice of the Midwest

Mills County averages 50.9°F annually, which is cooler than the national median but high for the region. It maintains a humid continental climate with 34.8 inches of annual precipitation.

Warmer Than the Iowa Average

The county sits 2.9 degrees above the Iowa state average of 48.0°F. This makes it one of the warmer regions in the state, particularly compared to northern counties.

Regional Warmth on the Border

Mills matches the 50.8°F average of neighboring Montgomery County but is significantly warmer than Monona to the north. It experiences a similar precipitation profile to its southern Iowa neighbors.

Hot Summers and Manageable Snow

Summer brings 34 days of extreme heat over 90°F, while winter is defined by 21.6 inches of snowfall. The temperature range spans from a 22.6°F January to a 75.8°F July.

Prepare for the Summer Surge

Residents should prioritize high-efficiency cooling to handle the month-plus of extreme heat days. Winter gear requirements are moderate, as the 21.6 inches of snow is lower than the northern state average.

Frequently Asked Questions

What is the average temperature in Mills County?
The average annual temperature in Mills County, IA is 50.9°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Mills County get?
Mills County receives an average of 34.8 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Mills County?
Yes, Mills County receives an average of 21.6 inches of snowfall per year according to NOAA climate normals.
How hot does Mills County get in summer?
The average summer temperature (June-August) in Mills County is 73.9°F. The county experiences an average of 34 days per year above 90°F.
How cold are winters in Mills County?
The average winter temperature (December-February) in Mills County is 25.8°F. January, typically the coldest month, averages 22.6°F.

Track your own weather in Mills County

Ambient Weather personal weather stations give you hyperlocal climate data.

Shop Weather Stations →

Sponsored

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.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor
← Back to Iowa