Lee County Climate
Lee County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
48.5°F
Annual Precip
37.6"
Annual Snowfall
29.6"
Extreme Heat Days
11
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
2,935
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Lee County
Climate Verdict
Lee County has a cool, averaging 48.5°F annually, moderate rainfall of 37.6 inches per year, rare extreme heat with only 10.933333333333332 days above 90°F annually, moderate snowfall of 29.6 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 72.4°F. Residents experience a substantial 52°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Lee County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Lee County is 4.4°F cooler than the Illinois statewide average of 52.8°F, it is somewhat drier than average for Illinois, the county experiences 16.327698863636364 fewer extreme heat days than the state average.
Climate Profile
About Lee County Weather
Cooler Northern Continental Climate
Lee County's annual average temperature of 48.5°F sits below the national median, reflecting its position in the upper Midwest. The region experiences a classic continental climate with distinct, sharp seasonal transitions.
One of Illinois’ Cooler Counties
At 48.5°F, Lee County is significantly cooler than the Illinois statewide average of 52.8°F. This temperature gap is driven primarily by its cold winter months, which average just 23.8°F.
Cooler and Snowier than Southern Peers
Lee County receives 29.6 inches of snow annually, nearly double what counties in central or southern Illinois typically see. Its 37.6 inches of rain is slightly below the state average, making for a drier but colder environment.
Harsh Winters and Brief Summers
Winter dominates with a January average of 20.5°F and nearly 30 inches of annual snow. Summers are relatively mild, with only 11 days per year reaching 90°F or higher.
Prepare for Snow and Cold
Residents should invest in heavy-duty snow removal equipment and ensure homes are well-insulated for the sub-freezing winter average. Cooling needs are modest, as the county enjoys a comfortable July average of 72.4°F.
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.