| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | September 21 - 30 |
| Average Last Frost Date: | May 11 - 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 58g - Worcester/Monadnock Plateau |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 03431 - Keene, NH | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 8 | 10 | 21 | 32 | 42 | 51 | 56 | 55 | 46 | 34 | 27 | 15 | 33 |
| Avg Max Temp (°F) | 30 | 33 | 42 | 55 | 68 | 76 | 81 | 79 | 70 | 59 | 46 | 34 | 56 |
| Avg Precip (In.) | 3.34 | 2.5 | 3.29 | 3.25 | 3.86 | 3.56 | 3.81 | 3.87 | 3.38 | 3.56 | 3.5 | 3.11 | 41.04 |