Haverhill, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.2 °C (low) to 13.5 °C (high). Annual precipitation averages 986.5 Millimeters. Haverhill is located in USDA Plant Hardiness Zone 5a. 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 | -14 °C | -1.8 °C | 61.21 mm |
| February | -14 °C | 0.2 °C | 52.83 mm |
| March | -8.1 °C | 5.3 °C | 61.98 mm |
| April | -1.2 °C | 12.8 °C | 74.93 mm |
| May | 5.4 °C | 20 °C | 86.61 mm |
| June | 10.5 °C | 24.7 °C | 100.84 mm |
| July | 13.6 °C | 27.6 °C | 104.9 mm |
| August | 12.4 °C | 26.9 °C | 95.25 mm |
| September | 8.3 °C | 22.7 °C | 90.68 mm |
| October | 1.7 °C | 14.8 °C | 106.43 mm |
| November | -3.4 °C | 7.9 °C | 71.12 mm |
| December | -9.3 °C | 1.4 °C | 79.76 mm |
| Annual | 0.2 °C | 13.5 °C | 986.54 mm |
| 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |