Willsboro, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.8 °F (low) to 55.5 °F (high). Annual precipitation averages 32.3 Inches. Willsboro is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.5 °F | 28.1 °F | 2.15 in. |
| February | 12.1 °F | 30.8 °F | 1.8 in. |
| March | 21.8 °F | 39.4 °F | 2.34 in. |
| April | 34.4 °F | 53.9 °F | 2.22 in. |
| May | 46.4 °F | 67.2 °F | 2.75 in. |
| June | 55.8 °F | 76.0 °F | 3.98 in. |
| July | 60.9 °F | 81.1 °F | 3.62 in. |
| August | 59.2 °F | 79.3 °F | 3.12 in. |
| September | 51.3 °F | 71.9 °F | 2.48 in. |
| October | 40.1 °F | 58.3 °F | 2.62 in. |
| November | 30.3 °F | 46.0 °F | 2.7 in. |
| December | 19.3 °F | 34.5 °F | 2.55 in. |
| Annual | 36.8 °F | 55.5 °F | 32.33 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |