Leominster, Massachusetts has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.1 °F (low) to 59.2 °F (high). Annual precipitation averages 50.1 Inches. Leominster is located in USDA Plant Hardiness Zone 6b. 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 | 14.9 °F | 34.1 °F | 3.92 in. |
| February | 16.6 °F | 36.8 °F | 3.51 in. |
| March | 24.6 °F | 44.5 °F | 4.59 in. |
| April | 35.4 °F | 57.7 °F | 4.26 in. |
| May | 46.2 °F | 68.8 °F | 3.87 in. |
| June | 55.7 °F | 77.5 °F | 4.34 in. |
| July | 61.4 °F | 83.2 °F | 3.91 in. |
| August | 59.6 °F | 81.6 °F | 3.61 in. |
| September | 51.4 °F | 74.5 °F | 4.22 in. |
| October | 39.7 °F | 62.0 °F | 5.25 in. |
| November | 30.1 °F | 50.2 °F | 4.04 in. |
| December | 21.5 °F | 39.6 °F | 4.59 in. |
| Annual | 38.1 °F | 59.2 °F | 50.11 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 6b : -5°F to 0°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 |