| 2023 Hardiness Zone: | 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: | 72d - Upper Mississippi Alluvial Plain |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 61264 - Milan, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 12 | 18 | 29 | 40 | 51 | 61 | 65 | 63 | 54 | 43 | 31 | 19 | 41 |
| Avg Max Temp (°F) | 29 | 35 | 48 | 61 | 73 | 82 | 86 | 83 | 76 | 64 | 48 | 34 | 60 |
| Avg Precip (In.) | 1.51 | 1.44 | 2.78 | 3.68 | 4.2 | 4.51 | 3.98 | 4.37 | 3.23 | 2.76 | 2.67 | 2.12 | 37.26 |