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Shelby County Climate

JanFebMarAprMayJunJulAugSepOctNovDec49.5°AVG °F

Avg Annual Temp

49.5°F

Annual Precip

34.3"

Annual Snowfall

30.5"

Extreme Heat Days

19

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
0.9"
1.0"
2.0"
3.3"
4.7"
5.2"
3.7"
4.3"
4.0"
2.4"
1.4"
1.3"
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

3,280

Supports most vegetables & fruits

Last spring frost (32°F): 04/27
First fall frost (32°F): 10/09

Seasonal Overview

Comfort ZoneSpring38°62°10.1"Summer72°75°13.2"Fall38°65°7.8"Winter21°26°3.2"20°40°60°80°100°

National Comparison

Warmer than 28% of US counties
Wetter than 33% of US counties
More seasonal variation than 91% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Shelby County

Climate Verdict

Shelby County has a cool, averaging 49.5°F annually, moderate rainfall of 34.3 inches per year, rare extreme heat with only 18.7 days above 90°F annually, moderate snowfall of 30.5 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 20.5°F. summers are warm — July averages 74.7°F. Residents experience a substantial 54°F difference between winter and summer.

Outdoor & Gardening Guidance

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

Regional Context

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

Climate Profile

About Shelby County Weather

Shelby County Sees Frequent Thermal Swings

The annual average temperature of 49.5°F reflects a classic continental climate with distinct, often harsh, seasonal changes. This average sits below the national median but remains typical for the American heartland.

Warmer Than the Iowa State Average

Shelby County's average temperature of 49.5°F is 1.5 degrees warmer than the statewide average of 48.0°F. This makes it one of the more temperate options within the state's borders.

Lighter Rainfall Than Eastern Iowa

The county records 34.3 inches of annual precipitation, trailing the state average of 36.1 inches. This slightly drier profile is common for counties situated in the western third of the state.

Snowy Winters and Significant Summer Heat

Residents experience 19 days of extreme heat over 90°F during summers that average 72.9°F. Winters bring an average of 30.5 inches of snow and January lows that hover around 20.5°F.

Dual Focus on Heat and Snow

Homeowners must prepare for nearly three weeks of 90°F heat while maintaining snow blowers for over 30 inches of winter accumulation. The 54-degree swing between January and July averages requires robust home insulation.

Frequently Asked Questions

What is the average temperature in Shelby County?
The average annual temperature in Shelby County, IA is 49.5°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Shelby County get?
Shelby County receives an average of 34.3 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 Shelby County?
Yes, Shelby County receives an average of 30.5 inches of snowfall per year according to NOAA climate normals.
How hot does Shelby County get in summer?
The average summer temperature (June-August) in Shelby County is 72.9°F. The county experiences an average of 19 days per year above 90°F.
How cold are winters in Shelby County?
The average winter temperature (December-February) in Shelby County is 23.7°F. January, typically the coldest month, averages 20.5°F.

Track your own weather in Shelby 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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