Barnstead, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.6 °F (low) to 56.6 °F (high). Annual precipitation averages 46.6 Inches. Barnstead 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 | 12.9 °F | 30.3 °F | 3.14 in. |
| February | 13.7 °F | 33.4 °F | 3.1 in. |
| March | 22.1 °F | 41.6 °F | 3.64 in. |
| April | 33.4 °F | 55.5 °F | 3.83 in. |
| May | 44.8 °F | 67.5 °F | 3.81 in. |
| June | 54.3 °F | 76.3 °F | 4.29 in. |
| July | 59.9 °F | 81.7 °F | 4.3 in. |
| August | 58.3 °F | 79.8 °F | 3.82 in. |
| September | 50.7 °F | 72.1 °F | 3.85 in. |
| October | 39.6 °F | 58.9 °F | 4.93 in. |
| November | 29.7 °F | 46.7 °F | 3.64 in. |
| December | 20.2 °F | 35.9 °F | 4.21 in. |
| Annual | 36.6 °F | 56.6 °F | 46.56 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |