Phillipston, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.9 °C (low) to 13.1 °C (high). Annual precipitation averages 1225.3 Millimeters. Phillipston is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.9 °C | -0.9 °C | 93.47 mm |
| February | -10.2 °C | 0.8 °C | 80.52 mm |
| March | -6.1 °C | 5 °C | 104.14 mm |
| April | 0.4 °C | 12.3 °C | 96.52 mm |
| May | 6.2 °C | 18.6 °C | 91.69 mm |
| June | 11.4 °C | 23.6 °C | 118.11 mm |
| July | 14.5 °C | 26.5 °C | 104.9 mm |
| August | 13.1 °C | 25.6 °C | 109.98 mm |
| September | 9.2 °C | 21.3 °C | 105.16 mm |
| October | 3.3 °C | 14.2 °C | 122.68 mm |
| November | -1.4 °C | 8.1 °C | 95.25 mm |
| December | -7.1 °C | 2.1 °C | 102.87 mm |
| Annual | 1.9 °C | 13.1 °C | 1225.29 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |