Acton, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.4 °F (low) to 59.7 °F (high). Annual precipitation averages 48.8 Inches. Acton 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.7 °F | 34.8 °F | 3.67 in. |
| February | 17.4 °F | 37.6 °F | 3.41 in. |
| March | 25.3 °F | 45.2 °F | 4.43 in. |
| April | 35.7 °F | 58.3 °F | 4.32 in. |
| May | 46.1 °F | 68.8 °F | 3.76 in. |
| June | 55.5 °F | 77.3 °F | 4.39 in. |
| July | 61.2 °F | 83.4 °F | 3.71 in. |
| August | 59.7 °F | 81.9 °F | 3.85 in. |
| September | 51.4 °F | 74.9 °F | 3.84 in. |
| October | 40.0 °F | 62.6 °F | 4.87 in. |
| November | 30.6 °F | 51.2 °F | 3.82 in. |
| December | 22.3 °F | 40.7 °F | 4.7 in. |
| Annual | 38.4 °F | 59.7 °F | 48.77 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |