West Boylston, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.5 °C (low) to 15 °C (high). Annual precipitation averages 1257.1 Millimeters. West Boylston is located in USDA Plant Hardiness Zone 6a. 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 | -9.2 °C | 1.2 °C | 96.27 mm |
| February | -8.4 °C | 2.7 °C | 84.33 mm |
| March | -4 °C | 6.9 °C | 115.32 mm |
| April | 1.9 °C | 14.2 °C | 107.95 mm |
| May | 7.9 °C | 20.2 °C | 93.47 mm |
| June | 13.2 °C | 24.8 °C | 107.44 mm |
| July | 16.3 °C | 27.9 °C | 99.31 mm |
| August | 15.4 °C | 27.1 °C | 107.44 mm |
| September | 10.8 °C | 23.2 °C | 103.38 mm |
| October | 4.5 °C | 16.6 °C | 129.29 mm |
| November | -0.8 °C | 10.2 °C | 97.28 mm |
| December | -5.5 °C | 4.4 °C | 115.57 mm |
| Annual | 3.5 °C | 15 °C | 1257.05 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |