Belmont, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.2 °C (low) to 13.4 °C (high). Annual precipitation averages 1182.6 Millimeters. Belmont 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 °C | -1.3 °C | 75.95 mm |
| February | -10.5 °C | 0.5 °C | 74.17 mm |
| March | -5.7 °C | 5.2 °C | 86.36 mm |
| April | 0.7 °C | 12.8 °C | 95.5 mm |
| May | 6.8 °C | 19.7 °C | 89.92 mm |
| June | 12 °C | 24.2 °C | 115.57 mm |
| July | 15.1 °C | 27.3 °C | 114.55 mm |
| August | 14.1 °C | 26.3 °C | 103.38 mm |
| September | 9.8 °C | 22.1 °C | 103.12 mm |
| October | 3.7 °C | 14.6 °C | 129.03 mm |
| November | -1.4 °C | 7.9 °C | 92.2 mm |
| December | -7 °C | 1.9 °C | 102.87 mm |
| Annual | 2.2 °C | 13.4 °C | 1182.62 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |