Belmont, Massachusetts has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 15.6 °C (high). Annual precipitation averages 1260.4 Millimeters. Belmont is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.5 °C | 2.4 °C | 100.33 mm |
| February | -6.6 °C | 3.8 °C | 90.93 mm |
| March | -2.5 °C | 7.7 °C | 121.41 mm |
| April | 3.2 °C | 14.4 °C | 109.22 mm |
| May | 8.7 °C | 20.2 °C | 93.73 mm |
| June | 13.9 °C | 25.2 °C | 106.93 mm |
| July | 17.2 °C | 28.4 °C | 95 mm |
| August | 16.4 °C | 27.6 °C | 97.54 mm |
| September | 12.2 °C | 23.7 °C | 96.77 mm |
| October | 5.9 °C | 17.1 °C | 122.43 mm |
| November | 0.7 °C | 11.2 °C | 102.62 mm |
| December | -3.9 °C | 5.5 °C | 123.44 mm |
| Annual | 4.8 °C | 15.6 °C | 1260.35 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |