Lexington, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.3 °F (low) to 60 °F (high). Annual precipitation averages 48.7 Inches. Lexington is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.0 °F | 35.4 °F | 3.81 in. |
| February | 18.8 °F | 38.2 °F | 3.45 in. |
| March | 26.1 °F | 46.2 °F | 4.6 in. |
| April | 36.4 °F | 58.3 °F | 4.18 in. |
| May | 46.4 °F | 68.6 °F | 3.66 in. |
| June | 55.8 °F | 77.4 °F | 4.19 in. |
| July | 61.7 °F | 83.3 °F | 3.68 in. |
| August | 60.3 °F | 81.9 °F | 3.77 in. |
| September | 52.5 °F | 74.8 °F | 3.72 in. |
| October | 41.3 °F | 62.5 °F | 4.82 in. |
| November | 31.8 °F | 51.7 °F | 4.0 in. |
| December | 23.5 °F | 41.2 °F | 4.77 in. |
| Annual | 39.3 °F | 60 °F | 48.65 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 |