Charlemont, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.5 °F (low) to 55 °F (high). Annual precipitation averages 51.1 Inches. Charlemont is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.7 °F | 30.3 °F | 3.61 in. |
| February | 12.7 °F | 33.0 °F | 3.34 in. |
| March | 20.7 °F | 40.9 °F | 4.08 in. |
| April | 31.9 °F | 53.2 °F | 4.05 in. |
| May | 42.7 °F | 64.9 °F | 4.2 in. |
| June | 51.6 °F | 73.7 °F | 4.88 in. |
| July | 57.0 °F | 78.8 °F | 4.44 in. |
| August | 55.2 °F | 77.1 °F | 4.05 in. |
| September | 47.8 °F | 70.2 °F | 5.04 in. |
| October | 36.9 °F | 57.3 °F | 5.14 in. |
| November | 27.6 °F | 45.8 °F | 3.78 in. |
| December | 18.6 °F | 35.0 °F | 4.47 in. |
| Annual | 34.5 °F | 55 °F | 51.08 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |