Harrisburg, IL Weather & Climate Normals
Harrisburg's real weather, in one number
Harrisburg, IL scores 45/100 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. 4 of the year's 12 months average between 55 and 75°F, the range this site counts as mild.
Harrisburg's hottest and coldest months
Harrisburg's hottest month is Jul, averaging 79°F; its coldest is Jan, averaging 34°F, a 45.3°F swing across the year, one of the widest gaps in this dataset.
Harrisburg's weather across the year
| Month | Avg high | Avg low | Precip |
|---|---|---|---|
| Jan | 43°F | 24°F | 3.79in |
| Feb | 48°F | 28°F | 3.13in |
| Mar | 58°F | 36°F | 4.9in |
| Apr | 69°F | 46°F | 5.26in |
| May | 78°F | 57°F | 4.31in |
| Jun | 86°F | 65°F | 4.92in |
| Jul | 89°F | 68°F | 3.49in |
| Aug | 88°F | 66°F | 3.58in |
| Sep | 82°F | 57°F | 3.1in |
| Oct | 71°F | 45°F | 3.76in |
| Nov | 57°F | 36°F | 3.97in |
| Dec | 47°F | 29°F | 3.38in |
Apr, May, Sep, and Oct are the best time to see Harrisburg at its mildest; the rest of the year, plan around Jul's heat and Jan's cold.
Rain and snow in Harrisburg
Over a typical year, Harrisburg sees about 47.59in of precipitation a year across roughly 92 days with measurable rain or snow. That station has no snowfall reading, so none is shown rather than assumed.
Where Harrisburg ranks
Harrisburg ranks 3539 of 4876 US cities in this dataset for comfort score, and 153 of 330 within IL. About 7,937 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from Harrisburg, IL US, 1.2 miles from Harrisburg, not a prediction for any specific day.
More on how this is worked out
Why some cities show no snow or rain figure · How the comfort score is calculated