Chelsea, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.1 °F (low) to 54.2 °F (high). Annual precipitation averages 40 Inches. Chelsea 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 | 5.9 °F | 27.3 °F | 2.67 in. |
| February | 6.3 °F | 30.4 °F | 2.17 in. |
| March | 16.2 °F | 38.9 °F | 2.9 in. |
| April | 29.0 °F | 52.6 °F | 3.08 in. |
| May | 40.5 °F | 66.0 °F | 3.32 in. |
| June | 49.6 °F | 74.5 °F | 4.18 in. |
| July | 54.6 °F | 79.0 °F | 4.54 in. |
| August | 52.4 °F | 77.6 °F | 3.86 in. |
| September | 45.0 °F | 70.4 °F | 3.27 in. |
| October | 34.3 °F | 56.8 °F | 3.96 in. |
| November | 25.1 °F | 44.2 °F | 2.88 in. |
| December | 14.0 °F | 32.5 °F | 3.18 in. |
| Annual | 31.1 °F | 54.2 °F | 40.01 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 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |