Westminster, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.4 °F (low) to 56 °F (high). Annual precipitation averages 49.2 Inches. Westminster is located in USDA Plant Hardiness Zone 6a. 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 | 13.5 °F | 30.8 °F | 3.68 in. |
| February | 14.8 °F | 33.9 °F | 3.35 in. |
| March | 22.5 °F | 41.5 °F | 4.35 in. |
| April | 33.6 °F | 54.7 °F | 4.07 in. |
| May | 43.8 °F | 66.1 °F | 3.83 in. |
| June | 53.5 °F | 74.5 °F | 4.33 in. |
| July | 59.1 °F | 79.7 °F | 4.07 in. |
| August | 57.3 °F | 78.2 °F | 4.07 in. |
| September | 50.4 °F | 71.0 °F | 4.18 in. |
| October | 39.0 °F | 58.2 °F | 5.0 in. |
| November | 29.2 °F | 46.8 °F | 3.86 in. |
| December | 20.4 °F | 36.2 °F | 4.42 in. |
| Annual | 36.4 °F | 56 °F | 49.21 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |