Lyme, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.3 °F (low) to 52.2 °F (high). Annual precipitation averages 44.4 Inches. Lyme 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 | 7.9 °F | 25.7 °F | 2.9 in. |
| February | 9.2 °F | 28.5 °F | 2.46 in. |
| March | 18.4 °F | 37.2 °F | 3.05 in. |
| April | 31.3 °F | 51.1 °F | 3.51 in. |
| May | 42.2 °F | 64.1 °F | 3.75 in. |
| June | 51.9 °F | 71.8 °F | 4.17 in. |
| July | 56.6 °F | 76.6 °F | 4.54 in. |
| August | 55.0 °F | 75.2 °F | 4.09 in. |
| September | 47.7 °F | 68.0 °F | 3.96 in. |
| October | 36.6 °F | 54.9 °F | 4.81 in. |
| November | 27.0 °F | 42.3 °F | 3.37 in. |
| December | 15.8 °F | 31.2 °F | 3.75 in. |
| Annual | 33.3 °F | 52.2 °F | 44.36 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |