Winooski, Vermont has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.8 °C (low) to 13.1 °C (high). Annual precipitation averages 1009.7 Millimeters. Winooski is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12 °C | -2.3 °C | 59.18 mm |
| February | -11.2 °C | -0.7 °C | 46.74 mm |
| March | -5.8 °C | 4.2 °C | 63.25 mm |
| April | 1.4 °C | 12.3 °C | 81.53 mm |
| May | 8.2 °C | 19.9 °C | 89.66 mm |
| June | 13.6 °C | 24.7 °C | 108.71 mm |
| July | 16.4 °C | 27.2 °C | 113.03 mm |
| August | 15.4 °C | 26.6 °C | 102.36 mm |
| September | 11.1 °C | 22.2 °C | 98.81 mm |
| October | 4.8 °C | 14.6 °C | 101.35 mm |
| November | -0.7 °C | 7.7 °C | 74.42 mm |
| December | -7.1 °C | 1.3 °C | 70.61 mm |
| Annual | 2.8 °C | 13.1 °C | 1009.65 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |