| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°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: | Sep. 21 - Sep. 30 | |
| Average Last Frost Date: | Jun. 1 - Jun. 10 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 58q - Sunapee Uplands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 03753 - Grantham, NH | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 8 | 10 | 19 | 30 | 41 | 50 | 55 | 53 | 45 | 35 | 26 | 15 | 32 |
| Avg Max Temp (°F) | 29 | 32 | 41 | 54 | 67 | 75 | 79 | 77 | 69 | 57 | 44 | 33 | 55 |
| Avg Precip (In.) | 3.66 | 2.78 | 3.29 | 3.59 | 3.93 | 3.8 | 4.23 | 4.19 | 4.35 | 3.92 | 3.71 | 3.33 | 44.79 |