| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 54a - Illinois/Indiana Prairies |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 60940 - Grant Park, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 18 | 28 | 38 | 49 | 58 | 63 | 60 | 53 | 41 | 31 | 20 | 40 |
| Avg Max Temp (°F) | 30 | 36 | 47 | 60 | 72 | 81 | 84 | 82 | 76 | 64 | 49 | 36 | 60 |
| Avg Precip (In.) | 1.69 | 1.57 | 2.76 | 3.89 | 4.42 | 4.81 | 4.01 | 3.79 | 3.32 | 3.11 | 3.49 | 2.6 | 39.46 |