Westford, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35 °F (low) to 55.4 °F (high). Annual precipitation averages 47.2 Inches. Westford is located in USDA Plant Hardiness Zone 5b. 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 | 13.1 °F | 30.8 °F | 3.3 in. |
| February | 13.9 °F | 32.4 °F | 2.76 in. |
| March | 21.0 °F | 40.7 °F | 3.64 in. |
| April | 31.8 °F | 54.5 °F | 4.12 in. |
| May | 42.1 °F | 66.8 °F | 3.87 in. |
| June | 51.7 °F | 73.7 °F | 4.77 in. |
| July | 56.1 °F | 78.0 °F | 4.61 in. |
| August | 54.8 °F | 76.8 °F | 4.59 in. |
| September | 48.3 °F | 70.3 °F | 4.02 in. |
| October | 37.9 °F | 58.5 °F | 4.32 in. |
| November | 28.6 °F | 46.1 °F | 3.55 in. |
| December | 20.8 °F | 35.8 °F | 3.67 in. |
| Annual | 35 °F | 55.4 °F | 47.22 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |