Summit, IL Weather & Climate Normals
Summit's real weather, in one number
Summit, 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.
Summit's hottest and coldest months
Summit's hottest month is Jul, averaging 76°F; its coldest is Jan, averaging 26°F, a 50.3°F swing across the year, one of the widest gaps in this dataset.
Summit's weather across the year
| Month | Avg high | Avg low | Precip |
|---|---|---|---|
| Jan | 33°F | 19°F | 1.48in |
| Feb | 37°F | 23°F | 1.46in |
| Mar | 48°F | 32°F | 1.88in |
| Apr | 60°F | 41°F | 3.57in |
| May | 71°F | 52°F | 4.09in |
| Jun | 81°F | 62°F | 4.01in |
| Jul | 85°F | 68°F | 3.55in |
| Aug | 83°F | 66°F | 3.99in |
| Sep | 76°F | 59°F | 2.77in |
| Oct | 63°F | 47°F | 3.48in |
| Nov | 49°F | 35°F | 2.35in |
| Dec | 38°F | 25°F | 1.79in |
May, Jun, Aug, Sep, and Oct are the best time to see Summit at its mildest; the rest of the year, plan around Jul's heat and Jan's cold.
Rain and snow in Summit
Over a typical year, Summit sees about 34.42in of precipitation a year across roughly 121 days with measurable rain or snow. That station has no snowfall reading, so none is shown rather than assumed.
Where Summit ranks
Summit ranks 2423 of 4876 US cities in this dataset for comfort score, and 64 of 330 within IL. About 10,761 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from Chicago Midway Ap, IL US, 3.2 miles from Summit, not a prediction for any specific day.
More on how this is worked out
Why some cities show no snow or rain figure · What a 30-year climate normal actually is