weatherbycounty

Cass County Climate

JanFebMarAprMayJunJulAugSepOctNovDec49.3°AVG °F

Avg Annual Temp

49.3°F

Annual Precip

36.8"

Annual Snowfall

27.3"

Extreme Heat Days

22

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
0.8"
1.2"
2.0"
3.7"
5.4"
5.4"
4.3"
4.4"
3.5"
2.9"
1.7"
1.4"
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

3,215

Supports most vegetables & fruits

Last spring frost (32°F): 04/30
First fall frost (32°F): 10/02

Seasonal Overview

Comfort ZoneSpring37°61°11.1"Summer71°75°14.1"Fall37°65°8.1"Winter21°26°3.4"20°40°60°80°100°

National Comparison

Warmer than 27% of US counties
Wetter than 38% of US counties
More seasonal variation than 91% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Cass County

Climate Verdict

Cass County has a cool, averaging 49.3°F annually, moderate rainfall of 36.8 inches per year, occasional hot days — 22.4 per year above 90°F, moderate snowfall of 27.3 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 20.6°F. summers are warm — July averages 74.8°F. Residents experience a substantial 54°F difference between winter and summer.

Outdoor & Gardening Guidance

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

Regional Context

Cass County closely matches the Iowa statewide average temperature of 48.0°F.

Climate Profile

About Cass County Weather

Closing the Gap on National Medians

Cass County averages 49.3°F annually, the warmest in this regional group and only 3.7 degrees below the national median. This southern-shifted location brings more intense summer heat to the local landscape.

Warmest of the Selected Counties

Averaging 1.3 degrees above the Iowa state mean of 48.0°F, Cass County represents the warmer side of the state. It also sees 36.8 inches of precipitation, slightly exceeding the state average.

More Heat than Northern Peers

Cass is significantly warmer than Carroll (48.3°F) and Calhoun (47.2°F). It receives less snow than northern counties, averaging 27.3 inches per year.

Significant Summer Highs

July averages 74.8°F, but the standout figure is the 22 days per year where temperatures exceed 90°F. Winters are the mildest in this set, with a January average of 20.6°F.

Prioritize Cooling and Hydration

The 22 days of extreme heat require residents to have reliable air conditioning and heat-safety plans. Lower snowfall of 27.3 inches makes winter travel easier here than in Iowa's northern counties.

Frequently Asked Questions

What is the average temperature in Cass County?
The average annual temperature in Cass County, IA is 49.3°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Cass County get?
Cass County receives an average of 36.8 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 Cass County?
Yes, Cass County receives an average of 27.3 inches of snowfall per year according to NOAA climate normals.
How hot does Cass County get in summer?
The average summer temperature (June-August) in Cass County is 72.9°F. The county experiences an average of 22 days per year above 90°F.
How cold are winters in Cass County?
The average winter temperature (December-February) in Cass County is 23.8°F. January, typically the coldest month, averages 20.6°F.

Track your own weather in Cass County

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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.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor
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