Worcester, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.6 °C (low) to 14.9 °C (high). Annual precipitation averages 1238.8 Millimeters. Worcester 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 | -9.1 °C | 1.3 °C | 95 mm |
| February | -8.3 °C | 2.8 °C | 83.06 mm |
| March | -3.9 °C | 7 °C | 117.35 mm |
| April | 1.9 °C | 14.3 °C | 107.44 mm |
| May | 7.9 °C | 20.2 °C | 93.47 mm |
| June | 13.2 °C | 24.8 °C | 106.17 mm |
| July | 16.3 °C | 27.8 °C | 97.28 mm |
| August | 15.4 °C | 26.9 °C | 101.85 mm |
| September | 10.9 °C | 23.1 °C | 100.08 mm |
| October | 4.5 °C | 16.4 °C | 128.52 mm |
| November | -0.8 °C | 10.2 °C | 93.98 mm |
| December | -5.4 °C | 4.4 °C | 114.55 mm |
| Annual | 3.6 °C | 14.9 °C | 1238.75 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |