| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 54f - Valparaiso-Wheaton Morainal Complex |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 60045 - Lake Forest, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 17 | 27 | 36 | 47 | 56 | 62 | 61 | 53 | 42 | 30 | 19 | 39 |
| Avg Max Temp (°F) | 29 | 33 | 43 | 55 | 66 | 77 | 81 | 80 | 73 | 61 | 47 | 34 | 57 |
| Avg Precip (In.) | 1.66 | 1.42 | 2.27 | 3.72 | 3.46 | 3.74 | 3.63 | 4.26 | 3.4 | 2.49 | 2.66 | 2.14 | 34.84 |