| 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: | 54a - Illinois/Indiana Prairies |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 60538 - Montgomery, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 11 | 16 | 27 | 37 | 47 | 56 | 61 | 59 | 51 | 39 | 28 | 17 | 37 |
| Avg Max Temp (°F) | 29 | 35 | 46 | 59 | 71 | 81 | 84 | 82 | 75 | 63 | 47 | 34 | 59 |
| Avg Precip (In.) | 1.65 | 1.52 | 2.55 | 3.81 | 3.94 | 4.37 | 4.28 | 4.29 | 3.48 | 2.69 | 3.13 | 2.39 | 38.1 |