| 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: | Oct. 1 - Oct. 10 | |
| Average Last Frost Date: | May 21 - May 31 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 58g - Worcester/Monadnock Plateau | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 03446 - Swanzey, NH | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 9 | 11 | 21 | 32 | 43 | 52 | 57 | 55 | 47 | 35 | 28 | 16 | 34 |
| Avg Max Temp (°F) | 30 | 34 | 43 | 56 | 69 | 77 | 82 | 79 | 71 | 60 | 47 | 35 | 57 |
| Avg Precip (In.) | 3.4 | 2.48 | 3.28 | 3.27 | 3.83 | 3.54 | 3.69 | 3.73 | 3.37 | 3.55 | 3.46 | 3.16 | 40.75 |