| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 54b - Chicago Lake Plain |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 60402 - Berwyn, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 15 | 20 | 30 | 39 | 50 | 59 | 65 | 64 | 55 | 44 | 33 | 21 | 41 |
| Avg Max Temp (°F) | 31 | 36 | 47 | 59 | 71 | 81 | 84 | 82 | 75 | 64 | 48 | 36 | 60 |
| Avg Precip (In.) | 1.87 | 1.66 | 2.75 | 3.75 | 3.74 | 4.14 | 3.83 | 4.1 | 3.37 | 2.72 | 3.19 | 2.6 | 37.71 |