Deerfield, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.9 °F (low) to 59.2 °F (high). Annual precipitation averages 49.8 Inches. Deerfield is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.6 °F | 33.2 °F | 3.55 in. |
| February | 14.9 °F | 36.7 °F | 3.18 in. |
| March | 23.5 °F | 45.0 °F | 3.76 in. |
| April | 34.1 °F | 58.1 °F | 3.87 in. |
| May | 45.1 °F | 69.6 °F | 3.98 in. |
| June | 54.8 °F | 78.5 °F | 4.86 in. |
| July | 59.9 °F | 83.6 °F | 4.22 in. |
| August | 58.1 °F | 81.9 °F | 4.53 in. |
| September | 50.2 °F | 74.4 °F | 4.78 in. |
| October | 38.7 °F | 61.3 °F | 4.92 in. |
| November | 29.2 °F | 49.3 °F | 3.7 in. |
| December | 20.7 °F | 38.6 °F | 4.48 in. |
| Annual | 36.9 °F | 59.2 °F | 49.83 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |