Derby Line, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.9 °F (low) to 51.7 °F (high). Annual precipitation averages 47.6 Inches. Derby Line is located in USDA Plant Hardiness Zone 4b. 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 | 4.6 °F | 23.9 °F | 3.29 in. |
| February | 6.0 °F | 26.8 °F | 2.72 in. |
| March | 16.2 °F | 35.9 °F | 3.11 in. |
| April | 29.6 °F | 50.1 °F | 3.57 in. |
| May | 41.8 °F | 64.1 °F | 4.27 in. |
| June | 51.3 °F | 72.6 °F | 5.15 in. |
| July | 56.0 °F | 77.1 °F | 4.92 in. |
| August | 54.3 °F | 75.6 °F | 4.51 in. |
| September | 46.6 °F | 68.2 °F | 3.85 in. |
| October | 36.1 °F | 54.6 °F | 4.64 in. |
| November | 25.8 °F | 41.5 °F | 3.61 in. |
| December | 14.1 °F | 30.3 °F | 3.98 in. |
| Annual | 31.9 °F | 51.7 °F | 47.62 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |