Waterloo, IL Weather & Climate Normals
Waterloo's real weather, in one number
Waterloo, IL scores 48/100 on this site's reading of NOAA's own 30-year normals: strongly seasonal. Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. 5 of the year's 12 months average between 55 and 75°F, the range this site counts as mild.
Waterloo's hottest and coldest months
Waterloo's hottest month is Jul, averaging 78°F; its coldest is Jan, averaging 32°F, a 46.1°F swing across the year, one of the widest gaps in this dataset.
Rain and snow in Waterloo
Waterloo averages 43.57in of precipitation a year across roughly 101 days with measurable rain or snow, and 9.2in of snow a year.
Where Waterloo ranks
Waterloo ranks 2418 of 4876 US cities in this dataset for comfort score, and 60 of 330 within IL. About 11,165 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from FESTUS, MO US, 15.3 miles from Waterloo, not a prediction for any specific day.
More on how this is worked out
What a 30-year climate normal actually is · Why this uses the nearest NOAA station