Lebanon, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.3 °F (low) to 56.3 °F (high). Annual precipitation averages 41.6 Inches. Lebanon is located in USDA Plant Hardiness Zone 5a. 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 | 9.0 °F | 28.9 °F | 2.77 in. |
| February | 10.2 °F | 32.5 °F | 2.43 in. |
| March | 19.7 °F | 41.2 °F | 3.16 in. |
| April | 31.8 °F | 55.4 °F | 3.26 in. |
| May | 43.4 °F | 68.1 °F | 3.44 in. |
| June | 52.6 °F | 76.3 °F | 4.17 in. |
| July | 57.8 °F | 81.4 °F | 4.29 in. |
| August | 55.9 °F | 79.7 °F | 3.6 in. |
| September | 48.5 °F | 72.6 °F | 3.48 in. |
| October | 37.1 °F | 58.6 °F | 4.36 in. |
| November | 27.6 °F | 46.0 °F | 3.14 in. |
| December | 17.4 °F | 34.4 °F | 3.45 in. |
| Annual | 34.3 °F | 56.3 °F | 41.55 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |