Billerica, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.9 °C (low) to 15.4 °C (high). Annual precipitation averages 1227.3 Millimeters. Billerica 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 | -8.6 °C | 1.7 °C | 94.74 mm |
| February | -7.6 °C | 3.3 °C | 86.61 mm |
| March | -3.4 °C | 7.4 °C | 115.57 mm |
| April | 2.3 °C | 14.4 °C | 104.14 mm |
| May | 7.9 °C | 20.2 °C | 93.73 mm |
| June | 13.1 °C | 25.2 °C | 106.93 mm |
| July | 16.3 °C | 28.4 °C | 94.49 mm |
| August | 15.5 °C | 27.6 °C | 94.49 mm |
| September | 11.2 °C | 23.7 °C | 95.5 mm |
| October | 4.8 °C | 16.8 °C | 122.43 mm |
| November | -0.3 °C | 10.7 °C | 99.82 mm |
| December | -4.9 °C | 4.9 °C | 118.87 mm |
| Annual | 3.9 °C | 15.4 °C | 1227.32 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |