Chester, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2 °C (low) to 14.4 °C (high). Annual precipitation averages 1524 Millimeters. Chester is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | 0.1 °C | 102.11 mm |
| February | -10.2 °C | 1.8 °C | 94.49 mm |
| March | -5.4 °C | 6.3 °C | 114.05 mm |
| April | 0.5 °C | 14 °C | 119.13 mm |
| May | 6.5 °C | 20.6 °C | 130.3 mm |
| June | 11.7 °C | 24.9 °C | 144.27 mm |
| July | 14.6 °C | 27.8 °C | 133.86 mm |
| August | 13.6 °C | 26.7 °C | 141.73 mm |
| September | 9.2 °C | 22.7 °C | 139.7 mm |
| October | 3.1 °C | 15.9 °C | 152.91 mm |
| November | -2.1 °C | 9.2 °C | 116.08 mm |
| December | -6.9 °C | 3.1 °C | 135.38 mm |
| Annual | 2 °C | 14.4 °C | 1524.01 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 |