| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°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: | 57a - Maumee Lake Plains |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 46743 - Harlan, IN | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 15 | 18 | 27 | 37 | 48 | 58 | 62 | 59 | 52 | 41 | 32 | 21 | 39 |
| Avg Max Temp (°F) | 31 | 35 | 47 | 59 | 71 | 80 | 84 | 82 | 75 | 63 | 48 | 36 | 59 |
| Avg Precip (In.) | 1.94 | 1.74 | 2.62 | 3.32 | 3.71 | 3.84 | 3.69 | 3.32 | 3.05 | 2.56 | 2.99 | 2.61 | 35.41 |