Maynard, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.8 °C (low) to 15.5 °C (high). Annual precipitation averages 1238.2 Millimeters. Maynard is located in USDA Plant Hardiness Zone 6b. 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 | -8.7 °C | 1.7 °C | 93.47 mm |
| February | -7.8 °C | 3.3 °C | 85.85 mm |
| March | -3.4 °C | 7.5 °C | 113.03 mm |
| April | 2.3 °C | 14.7 °C | 109.47 mm |
| May | 7.9 °C | 20.5 °C | 94.74 mm |
| June | 13.2 °C | 25.2 °C | 111.25 mm |
| July | 16.4 °C | 28.6 °C | 94.23 mm |
| August | 15.7 °C | 27.8 °C | 97.79 mm |
| September | 11.1 °C | 23.9 °C | 97.79 mm |
| October | 4.8 °C | 17.1 °C | 123.95 mm |
| November | -0.4 °C | 10.8 °C | 97.03 mm |
| December | -5.1 °C | 4.9 °C | 119.63 mm |
| Annual | 3.8 °C | 15.5 °C | 1238.23 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 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 |