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Warren County Climate

JanFebMarAprMayJunJulAugSepOctNovDec50.3°AVG °F

Avg Annual Temp

50.3°F

Annual Precip

39.2"

Annual Snowfall

25.6"

Extreme Heat Days

19

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
1.8"
1.8"
2.5"
3.9"
5.3"
4.8"
4.0"
3.8"
3.8"
3.0"
2.5"
2.0"
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

3,257

Supports most vegetables & fruits

Last spring frost (32°F): 04/22
First fall frost (32°F): 10/15

Seasonal Overview

Comfort ZoneSpring39°62°11.8"Summer71°74°12.6"Fall40°65°9.3"Winter23°28°5.6"20°40°60°80°100°

National Comparison

Warmer than 31% of US counties
Wetter than 44% of US counties
More seasonal variation than 84% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Warren County

Climate Verdict

Warren County has a mild, with an average annual temperature of 50.3°F, moderate rainfall of 39.2 inches per year, rare extreme heat with only 18.55 days above 90°F annually, moderate snowfall of 25.6 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 73.8°F. Residents experience a substantial 51°F difference between winter and summer.

Outdoor & Gardening Guidance

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

Regional Context

Warren County closely matches the Illinois statewide average temperature of 52.8°F, it is somewhat drier than average for Illinois.

Climate Profile

About Warren County Weather

Cooler than the national average

Warren County averages 50.3°F annually, which is cooler than the national median temperature. It sees 39.2 inches of precipitation, slightly lower than the typical Illinois baseline.

Below the Illinois temperature average

The county's 50.3°F average sits 2.5 degrees below the state average of 52.8°F. This puts Warren in the colder half of the state, reflective of its west-central location.

Snowier than its southern peers

Warren County receives 25.6 inches of snow, more than double the amount seen in southern counties like Wayne. It shares a similar climate profile with northern neighbor Whiteside County, though it is slightly warmer.

Significant snowfall and crisp winters

Winters are cold with a January average of 22.6°F and over two feet of total annual snow. Summers are pleasant but brief, featuring only 19 days of extreme heat above 90°F.

Winterize for snow and cold

Heavier winter gear and snow removal equipment are essential for the 25.6 inches of annual snowfall. Residents should also ensure home insulation is sufficient for January temperatures that regularly dip into the low 20s.

Frequently Asked Questions

What is the average temperature in Warren County?
The average annual temperature in Warren County, IL is 50.3°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Warren County get?
Warren County receives an average of 39.2 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 Warren County?
Yes, Warren County receives an average of 25.6 inches of snowfall per year according to NOAA climate normals.
How hot does Warren County get in summer?
The average summer temperature (June-August) in Warren County is 72.2°F. The county experiences an average of 19 days per year above 90°F.
How cold are winters in Warren County?
The average winter temperature (December-February) in Warren County is 25.9°F. January, typically the coldest month, averages 22.6°F.

Track your own weather in Warren 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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