Brookfield, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3 °C (low) to 14.5 °C (high). Annual precipitation averages 1231.1 Millimeters. Brookfield is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.5 °C | 0.9 °C | 93.22 mm |
| February | -9.2 °C | 2.3 °C | 82.55 mm |
| March | -4.6 °C | 6.7 °C | 106.93 mm |
| April | 1.3 °C | 13.8 °C | 102.11 mm |
| May | 7.3 °C | 19.9 °C | 91.19 mm |
| June | 12.4 °C | 24.5 °C | 106.17 mm |
| July | 15.7 °C | 27.3 °C | 103.63 mm |
| August | 14.7 °C | 26.4 °C | 111 mm |
| September | 10.4 °C | 22.5 °C | 108.46 mm |
| October | 4 °C | 15.8 °C | 120.65 mm |
| November | -1.1 °C | 9.7 °C | 94.23 mm |
| December | -5.8 °C | 3.9 °C | 111 mm |
| Annual | 3 °C | 14.5 °C | 1231.14 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |