Newmarket, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.1 °F (low) to 58.1 °F (high). Annual precipitation averages 46.1 Inches. Newmarket is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.8 °F | 33.5 °F | 3.13 in. |
| February | 16.4 °F | 36.2 °F | 3.14 in. |
| March | 24.2 °F | 43.7 °F | 3.91 in. |
| April | 34.2 °F | 55.9 °F | 4.2 in. |
| May | 44.2 °F | 66.5 °F | 3.72 in. |
| June | 53.8 °F | 76.1 °F | 4.09 in. |
| July | 59.5 °F | 81.6 °F | 3.82 in. |
| August | 58.0 °F | 80.7 °F | 3.54 in. |
| September | 50.2 °F | 73.2 °F | 3.88 in. |
| October | 38.8 °F | 61.0 °F | 4.61 in. |
| November | 30.1 °F | 49.7 °F | 3.84 in. |
| December | 21.5 °F | 38.6 °F | 4.26 in. |
| Annual | 37.1 °F | 58.1 °F | 46.14 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |