LaSalle County Climate

LaSalle County, Illinois

JanFebMarAprMayJunJulAugSepOctNovDec49.8°AVG °F

Avg Annual Temp

49.8°F

Annual Precip

38.0"

Annual Snowfall

25.6"

Extreme Heat Days

17.066666666666666

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
1.9"
1.8"
2.3"
3.6"
4.6"
4.6"
4.0"
3.8"
3.4"
3.3"
2.6"
2.0"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring38°61°10.6"Summer70°73°12.5"Fall40°65°9.3"Winter23°28°5.7"20°40°60°80°100°

National Comparison

Warmer than 30% of US counties
Wetter than 40% of US counties
More seasonal variation than 78% of US counties

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

What is the average temperature in LaSalle County?
The average annual temperature in LaSalle County, IL is 49.8°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does LaSalle County get?
LaSalle County receives an average of 38.0 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 LaSalle County?
Yes, LaSalle County receives an average of 25.6 inches of snowfall per year according to NOAA climate normals.
How hot does LaSalle County get in summer?
The average summer temperature (June-August) in LaSalle County is 71.7°F. The county experiences an average of 17.066666666666666 days per year above 90°F.
How cold are winters in LaSalle County?
The average winter temperature (December-February) in LaSalle County is 25.7°F. January, typically the coldest month, averages 22.6°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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