Williamsville, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.4 °C (low) to 14 °C (high). Annual precipitation averages 1022.6 Millimeters. Williamsville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.6 °C | 0.2 °C | 78.99 mm |
| February | -7.6 °C | 0.9 °C | 60.96 mm |
| March | -3.8 °C | 5.5 °C | 73.66 mm |
| April | 2.1 °C | 12.7 °C | 84.84 mm |
| May | 8.4 °C | 19.8 °C | 83.82 mm |
| June | 13.9 °C | 24.7 °C | 94.49 mm |
| July | 16.7 °C | 27.1 °C | 85.6 mm |
| August | 15.9 °C | 26.5 °C | 82.3 mm |
| September | 12 °C | 22.9 °C | 105.16 mm |
| October | 6.1 °C | 15.8 °C | 99.06 mm |
| November | 0.7 °C | 8.9 °C | 86.61 mm |
| December | -4 °C | 3.2 °C | 87.12 mm |
| Annual | 4.4 °C | 14 °C | 1022.61 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |