DeKalb, IL Weather & Climate Normals
DeKalb's real weather, in one number
DeKalb, IL scores 43/100 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.
DeKalb's hottest and coldest months
DeKalb's hottest month is Jul, averaging 73°F; its coldest is Jan, averaging 21°F, a 52.6°F swing across the year, one of the widest gaps in this dataset.
DeKalb's weather across the year
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 28°F | 13°F | 1.69in | 10.2in |
| Feb | 33°F | 17°F | 1.71in | 8.7in |
| Mar | 45°F | 27°F | 2.24in | 4.4in |
| Apr | 59°F | 37°F | 3.56in | 1.3in |
| May | 70°F | 49°F | 4.79in | 0in |
| Jun | 80°F | 60°F | 4.57in | 0in |
| Jul | 83°F | 63°F | 4in | 0in |
| Aug | 81°F | 61°F | 4.06in | 0in |
| Sep | 75°F | 53°F | 3.32in | 0in |
| Oct | 62°F | 41°F | 2.96in | 0.1in |
| Nov | 46°F | 30°F | 2.31in | 1.8in |
| Dec | 34°F | 19°F | 2.04in | 6.6in |
May, Jun, Jul, Aug, and Sep are the best time to see DeKalb at its mildest; the rest of the year, plan around Jan's cold.
Rain and snow in DeKalb
DeKalb averages 37.25in of precipitation a year across roughly 121 days with measurable rain or snow, and 33.1in of snow a year.
Where DeKalb ranks
DeKalb ranks 3976 of 4876 US cities in this dataset for comfort score, and 233 of 330 within IL. About 40,491 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from De Kalb, IL US, 1.5 miles from DeKalb, not a prediction for any specific day.
More on how this is worked out
How the comfort score is calculated · Why some cities show no snow or rain figure