Putnam County Climate

Putnam County, Illinois

JanFebMarAprMayJunJulAugSepOctNovDec51.0°AVG °F

Avg Annual Temp

51.0°F

Annual Precip

Annual Snowfall

Extreme Heat Days

29

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Precipitation data coming soon

Seasonal Overview

Comfort ZoneSpring39°62°0.0"Summer71°75°0.0"Fall41°66°0.0"Winter24°29°0.0"20°40°60°80°100°

National Comparison

Warmer than 35% of US counties

Data pending

More seasonal variation than 78% of US counties

Climate Profile

About Putnam County Weather

Cooler Northern Temperate Climate

Putnam County averages 51.0°F annually, which is cooler than the national median. This reflects a typical upper-Midwest profile where winter temperatures significantly influence the yearly average.

Below the Illinois Average

The county's 51.0°F annual average sits below the Illinois state average of 52.8°F. While precipitation and snowfall data are limited, its temperature profile suggests a classic northern Illinois environment.

Cooler than Southern Peers

Putnam is nearly 7 degrees cooler on average than southern counties like Pulaski. It records 29 days of extreme heat, which is fewer than Pike County but still indicates warm summer peaks.

Chilly Winters and Mild Summers

January is particularly cold with an average of 23.8°F, dragging the winter average down to 26.9°F. Summer provides relief with a July average of 74.8°F and 29 days reaching at least 90°F.

Focus on Winter Readiness

High-efficiency heating and proper insulation are the top priorities given the cold 23.8°F January average. Residents should also plan for nearly a month of extreme heat during the summer season.

Frequently Asked Questions

What is the average temperature in Putnam County?
The average annual temperature in Putnam County, IL is 51.0°F, based on NOAA 30-year climate normals (1991-2020).
How hot does Putnam County get in summer?
The average summer temperature (June-August) in Putnam County is 73.0°F. The county experiences an average of 29 days per year above 90°F.
How cold are winters in Putnam County?
The average winter temperature (December-February) in Putnam County is 26.9°F. January, typically the coldest month, averages 23.8°F.

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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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