| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F |
| 2012 Hardiness Zone: | Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F |
| 1990 Hardiness Zone: | Zone 4a: -30F to -25F |
| Average First Frost Date: | Sep.11 - Sep. 20 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfc - Subarctic With Cool Summers And Year Around Rainfall |
| Ecoregion: | 58n - White Mountain Foothills |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 03583 - Jefferson, NH | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 4 | 6 | 17 | 29 | 40 | 49 | 54 | 52 | 44 | 33 | 25 | 11 | 30 |
| Avg Max Temp (°F) | 25 | 29 | 38 | 50 | 65 | 72 | 77 | 74 | 66 | 54 | 41 | 30 | 52 |
| Avg Precip (In.) | 4.44 | 3.47 | 4.76 | 4.48 | 4.62 | 5.22 | 5.02 | 5.18 | 4.94 | 4.56 | 5.13 | 4.66 | 56.47 |