Putnam County Climate
Putnam County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.0°F
Annual Precip
—
Annual Snowfall
—
Extreme Heat Days
29
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
3,355
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Putnam County
Climate Verdict
Putnam County has a mild, with an average annual temperature of 51.0°F, occasional hot days — 29 per year above 90°F. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 23.8°F. summers are warm — July averages 74.8°F. Residents experience a substantial 51°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Putnam County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Putnam County closely matches the Illinois statewide average temperature of 52.8°F.
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
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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.