Medfield, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.9 °F (low) to 60.3 °F (high). Annual precipitation averages 49.5 Inches. Medfield 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.1 °F | 36.7 °F | 3.97 in. |
| February | 19.6 °F | 39.2 °F | 3.4 in. |
| March | 26.9 °F | 46.4 °F | 4.74 in. |
| April | 36.9 °F | 58.5 °F | 4.44 in. |
| May | 46.9 °F | 68.9 °F | 3.58 in. |
| June | 56.2 °F | 77.5 °F | 4.19 in. |
| July | 62.2 °F | 83.2 °F | 3.57 in. |
| August | 60.6 °F | 81.8 °F | 3.92 in. |
| September | 53.2 °F | 74.8 °F | 3.84 in. |
| October | 41.6 °F | 62.9 °F | 4.92 in. |
| November | 32.5 °F | 52.2 °F | 4.11 in. |
| December | 24.3 °F | 42.0 °F | 4.8 in. |
| Annual | 39.9 °F | 60.3 °F | 49.48 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |