Sanbornton, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.9 °F (low) to 56 °F (high). Annual precipitation averages 48 Inches. Sanbornton is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.1 °F | 29.3 °F | 3.17 in. |
| February | 11.9 °F | 32.6 °F | 2.98 in. |
| March | 20.8 °F | 41.2 °F | 3.53 in. |
| April | 32.1 °F | 54.7 °F | 3.86 in. |
| May | 43.3 °F | 67.4 °F | 3.84 in. |
| June | 52.7 °F | 75.7 °F | 4.52 in. |
| July | 57.6 °F | 81.2 °F | 4.6 in. |
| August | 56.2 °F | 79.4 °F | 4.11 in. |
| September | 48.4 °F | 71.6 °F | 3.98 in. |
| October | 37.7 °F | 58.0 °F | 5.29 in. |
| November | 28.4 °F | 45.8 °F | 3.96 in. |
| December | 18.6 °F | 34.9 °F | 4.18 in. |
| Annual | 34.9 °F | 56 °F | 48.02 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |