Harvard, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.5 °F (low) to 59.4 °F (high). Annual precipitation averages 48.9 Inches. Harvard is located in USDA Plant Hardiness Zone 6a. 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 | 15.5 °F | 34.3 °F | 3.66 in. |
| February | 17.0 °F | 37.0 °F | 3.39 in. |
| March | 25.1 °F | 44.7 °F | 4.38 in. |
| April | 35.7 °F | 57.9 °F | 4.17 in. |
| May | 46.5 °F | 68.8 °F | 3.76 in. |
| June | 56.0 °F | 77.4 °F | 4.44 in. |
| July | 61.7 °F | 83.1 °F | 3.76 in. |
| August | 60.0 °F | 81.6 °F | 3.99 in. |
| September | 51.8 °F | 74.6 °F | 4.03 in. |
| October | 40.2 °F | 62.1 °F | 4.9 in. |
| November | 30.6 °F | 50.7 °F | 3.87 in. |
| December | 22.1 °F | 40.1 °F | 4.57 in. |
| Annual | 38.5 °F | 59.4 °F | 48.92 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 |