Northfield, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.3 °F (low) to 58.7 °F (high). Annual precipitation averages 47.6 Inches. Northfield is located in USDA Plant Hardiness Zone 5b. 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 | 12.7 °F | 32.4 °F | 3.56 in. |
| February | 13.9 °F | 35.8 °F | 3.09 in. |
| March | 22.9 °F | 44.2 °F | 3.73 in. |
| April | 33.5 °F | 57.5 °F | 3.69 in. |
| May | 44.6 °F | 69.4 °F | 3.62 in. |
| June | 54.3 °F | 78.2 °F | 4.52 in. |
| July | 59.4 °F | 83.4 °F | 4.13 in. |
| August | 57.7 °F | 81.8 °F | 4.26 in. |
| September | 49.7 °F | 74.2 °F | 4.25 in. |
| October | 38.2 °F | 60.9 °F | 4.93 in. |
| November | 28.9 °F | 48.5 °F | 3.68 in. |
| December | 19.9 °F | 37.8 °F | 4.15 in. |
| Annual | 36.3 °F | 58.7 °F | 47.61 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |