| 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. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 55a - Clayey High Lime Till Plains |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 46733 - Decatur, IN | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 16 | 19 | 29 | 39 | 50 | 59 | 63 | 61 | 53 | 42 | 33 | 22 | 40 |
| Avg Max Temp (°F) | 31 | 36 | 47 | 60 | 71 | 80 | 84 | 82 | 76 | 63 | 49 | 36 | 60 |
| Avg Precip (In.) | 1.91 | 1.64 | 2.63 | 3.33 | 3.77 | 3.94 | 3.78 | 3.43 | 2.87 | 2.47 | 2.88 | 2.49 | 35.16 |