| 2023 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate |
| Ecoregion: | 72j - Southern Illinoian Till Plain |
| Heat Zone Days: | 61 - 90 days Over 86°F |
Annual Climate Data for ZIP Code 62859 - Mc Leansboro, IL | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 21 | 24 | 34 | 44 | 53 | 62 | 66 | 63 | 56 | 44 | 35 | 25 | 44 |
| Avg Max Temp (°F) | 39 | 45 | 55 | 66 | 76 | 85 | 89 | 88 | 81 | 70 | 56 | 44 | 66 |
| Avg Precip (In.) | 3.05 | 2.77 | 4.38 | 4.53 | 4.69 | 3.89 | 3.54 | 3.01 | 2.92 | 2.99 | 4.47 | 3.58 | 43.82 |