Stow, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.7 °C (low) to 15.4 °C (high). Annual precipitation averages 1243.6 Millimeters. Stow 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 | -8.9 °C | 1.6 °C | 93.73 mm |
| February | -8 °C | 3.2 °C | 86.87 mm |
| March | -3.6 °C | 7.4 °C | 113.03 mm |
| April | 2.2 °C | 14.7 °C | 110.74 mm |
| May | 8 °C | 20.5 °C | 95.25 mm |
| June | 13.2 °C | 25.2 °C | 112.01 mm |
| July | 16.4 °C | 28.6 °C | 94.49 mm |
| August | 15.6 °C | 27.7 °C | 98.04 mm |
| September | 11 °C | 23.8 °C | 99.06 mm |
| October | 4.7 °C | 17.1 °C | 123.95 mm |
| November | -0.6 °C | 10.7 °C | 96.77 mm |
| December | -5.3 °C | 4.8 °C | 119.63 mm |
| Annual | 3.7 °C | 15.4 °C | 1243.57 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 |