LaSalle County Climate
LaSalle County, Illinois
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
49.8°F
Annual Precip
38.0"
Annual Snowfall
25.6"
Extreme Heat Days
17
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
3,136
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: LaSalle County
Climate Verdict
LaSalle County has a cool, averaging 49.8°F annually, moderate rainfall of 38.0 inches per year, rare extreme heat with only 17.066666666666666 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 73.4°F. Residents experience a substantial 51°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for LaSalle County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
LaSalle County closely matches the Illinois statewide average temperature of 52.8°F, it is somewhat drier than average for Illinois.
Climate Profile
About LaSalle County Weather
Typical central continental weather
LaSalle County averages 49.8°F, which is cooler than the national median for annual temperature. Its 38.0 inches of precipitation is also slightly below the national average for the eastern half of the U.S.
Cooler and drier than average
At 49.8°F, the county is three degrees cooler than the Illinois state average of 52.8°F. It is also drier than the state average, receiving 38.0 inches of rain compared to 41.7 inches.
Mirroring the heart of Illinois
LaSalle’s climate nearly matches Knox County’s 49.9°F average temperature. However, it is slightly drier than Kendall County, which receives two additional inches of annual precipitation.
Consistent seasonal temperature swings
The area sees 17 days of extreme heat above 90°F each summer. Winter is standard for the region, with an average temperature of 25.7°F and 25.6 inches of snowfall.
Balance heating and cooling needs
Moderate snowfall of 25.6 inches requires standard winter maintenance tools. Residents should also prepare for 17 days of extreme summer heat with reliable home cooling systems.
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.