Londonderry, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.3 °F (low) to 54 °F (high). Annual precipitation averages 48.1 Inches. Londonderry is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 9.2 °F | 28.7 °F | 3.64 in. |
| February | 9.1 °F | 31.3 °F | 3.02 in. |
| March | 17.7 °F | 39.4 °F | 3.81 in. |
| April | 29.7 °F | 52.2 °F | 3.78 in. |
| May | 41.7 °F | 64.9 °F | 3.81 in. |
| June | 50.6 °F | 73.0 °F | 4.54 in. |
| July | 54.9 °F | 77.9 °F | 4.24 in. |
| August | 53.0 °F | 76.2 °F | 4.19 in. |
| September | 44.9 °F | 69.7 °F | 3.93 in. |
| October | 34.6 °F | 56.4 °F | 5.1 in. |
| November | 25.4 °F | 44.8 °F | 3.95 in. |
| December | 16.4 °F | 33.7 °F | 4.09 in. |
| Annual | 32.3 °F | 54 °F | 48.1 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| 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 |