Hamilton, Massachusetts has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.3 °C (low) to 14.8 °C (high). Annual precipitation averages 1235.2 Millimeters. Hamilton 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 | -6.8 °C | 2.3 °C | 97.28 mm |
| February | -5.9 °C | 3.5 °C | 89.92 mm |
| March | -2.1 °C | 7.1 °C | 122.68 mm |
| April | 3.4 °C | 13.4 °C | 107.44 mm |
| May | 8.8 °C | 18.8 °C | 91.95 mm |
| June | 14.2 °C | 23.9 °C | 108.2 mm |
| July | 17.3 °C | 27.3 °C | 89.15 mm |
| August | 16.7 °C | 26.6 °C | 86.61 mm |
| September | 12.7 °C | 22.7 °C | 96.01 mm |
| October | 6.6 °C | 16.4 °C | 121.41 mm |
| November | 1.4 °C | 10.7 °C | 101.09 mm |
| December | -3.3 °C | 5.3 °C | 123.44 mm |
| Annual | 5.3 °C | 14.8 °C | 1235.18 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 |