| 2023 Hardiness Zone: | Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | 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. 11 - Oct. 20 | |
| Average Last Frost Date: | May 11 - May 20 | |
| 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 03837 - Gilmanton Iron Works, NH | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 11 | 22 | 32 | 43 | 53 | 57 | 56 | 47 | 37 | 29 | 17 | 34 |
| Avg Max Temp (°F) | 28 | 32 | 41 | 54 | 66 | 75 | 79 | 77 | 69 | 58 | 45 | 33 | 55 |
| Avg Precip (In.) | 3.34 | 2.59 | 3.13 | 3.54 | 3.64 | 3.72 | 4.02 | 3.73 | 3.45 | 4 | 3.92 | 3.25 | 42.33 |