Leicester, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.3 °C (low) to 13.6 °C (high). Annual precipitation averages 1267.5 Millimeters. Leicester is located in USDA Plant Hardiness Zone 6b. 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 | -8.5 °C | 0.1 °C | 97.54 mm |
| February | -7.6 °C | 1.6 °C | 85.6 mm |
| March | -3.4 °C | 5.8 °C | 116.08 mm |
| April | 2.7 °C | 12.9 °C | 109.22 mm |
| May | 8.3 °C | 18.9 °C | 92.2 mm |
| June | 13.7 °C | 23.5 °C | 108.97 mm |
| July | 16.7 °C | 26.4 °C | 100.08 mm |
| August | 16 °C | 25.6 °C | 107.19 mm |
| September | 12.2 °C | 21.7 °C | 106.43 mm |
| October | 5.6 °C | 15.1 °C | 129.54 mm |
| November | 0.1 °C | 8.9 °C | 98.04 mm |
| December | -4.8 °C | 3.2 °C | 116.59 mm |
| Annual | 4.3 °C | 13.6 °C | 1267.48 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 6b : -20.6°C to -17.8°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 |