Litchfield, New Hampshire has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.2 °F (low) to 59.2 °F (high). Annual precipitation averages 46.3 Inches. Litchfield 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.8 °F | 33.9 °F | 3.3 in. |
| February | 15.5 °F | 36.9 °F | 3.19 in. |
| March | 23.8 °F | 44.7 °F | 4.04 in. |
| April | 34.5 °F | 57.9 °F | 3.99 in. |
| May | 45.5 °F | 69.0 °F | 3.7 in. |
| June | 54.9 °F | 78.0 °F | 4.17 in. |
| July | 60.5 °F | 83.4 °F | 3.58 in. |
| August | 58.7 °F | 81.8 °F | 3.73 in. |
| September | 50.8 °F | 74.4 °F | 3.79 in. |
| October | 38.7 °F | 61.6 °F | 4.74 in. |
| November | 29.4 °F | 49.9 °F | 3.77 in. |
| December | 20.6 °F | 39.3 °F | 4.27 in. |
| Annual | 37.2 °F | 59.2 °F | 46.27 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |