McLean County Climate
McLean County, Illinois
Avg Annual Temp
50.6°F
Annual Precip
38.7"
Annual Snowfall
15.5"
Extreme Heat Days
25.166666666666668
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About McLean County Weather
Standardized Central Illinois Weather Patterns
McLean County's 50.6°F average annual temperature is slightly below the national median for temperate climates. It features reliable seasonal patterns common to the American breadbasket.
Just Below the State Average
At 50.6°F, McLean is over two degrees cooler than the Illinois state average of 52.8°F. Its 38.7 inches of annual precipitation is also lower than the state's 41.7-inch average.
Similar to Western Peers Like Mercer
McLean's average temperature of 50.6°F exactly matches Mercer County, though McLean sees less snow. It experiences 25 extreme heat days, placing it in the middle of the regional spectrum.
A Mix of Humidity and Frost
July averages reach 73.9°F, accompanied by 25 days where the mercury hits at least 90°F. Winter brings a January average of 23.7°F and about 15.5 inches of total snowfall.
Prepare for Moderate Snow and Heat
Expect roughly 15.5 inches of snow each winter, requiring basic removal tools. Check your insulation to keep the home efficient during the 25 days of extreme summer heat.
Frequently Asked Questions
What is the average temperature in McLean County?
How much rain does McLean County get?
Does it snow in McLean County?
How hot does McLean County get in summer?
How cold are winters in McLean County?
Track your own weather in McLean County
Ambient Weather personal weather stations give you hyperlocal climate data.
Sponsored
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.