Lake Forest, IL Weather & Climate Normals
Lake Forest's real weather, in one number
Lake Forest, IL scores 44/100 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.
Lake Forest's hottest and coldest months
Lake Forest's hottest month is Jul, averaging 74°F; its coldest is Jan, averaging 24°F, a 49.2°F swing across the year, one of the widest gaps in this dataset.
Lake Forest's weather across the year
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 32°F | 16°F | 2.1in | 11.3in |
| Feb | 36°F | 19°F | 1.98in | 7.7in |
| Mar | 46°F | 28°F | 2.26in | 5.6in |
| Apr | 57°F | 38°F | 4in | 1.1in |
| May | 68°F | 48°F | 4.84in | 0in |
| Jun | 78°F | 57°F | 4.31in | 0in |
| Jul | 84°F | 63°F | 3.74in | 0in |
| Aug | 82°F | 62°F | 4.16in | 0in |
| Sep | 75°F | 55°F | 3.56in | 0in |
| Oct | 63°F | 43°F | 3.59in | 0.1in |
| Nov | 49°F | 33°F | 2.63in | 1.9in |
| Dec | 38°F | 22°F | 2.34in | 5.9in |
May, Jun, Jul, Aug, and Sep are the best time to see Lake Forest at its mildest; the rest of the year, plan around Jan's cold.
Rain and snow in Lake Forest
Lake Forest averages 39.51in of precipitation a year across roughly 130 days with measurable rain or snow, and 33.6in of snow a year.
Where Lake Forest ranks
Lake Forest ranks 3766 of 4876 US cities in this dataset for comfort score, and 194 of 330 within IL. About 19,642 people live there.
If you need tomorrow's forecast, not the 30-year average
Everything above is a 30-year average from Chicago Botanic Garden, IL US, 7.5 miles from Lake Forest, 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