Windham, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1 °C (low) to 13.5 °C (high). Annual precipitation averages 1152.7 Millimeters. Windham is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.3 °C | -0.2 °C | 76.71 mm |
| February | -10.3 °C | 1.6 °C | 63.5 mm |
| March | -6.8 °C | 5.2 °C | 90.68 mm |
| April | -0.7 °C | 12.9 °C | 93.22 mm |
| May | 5.3 °C | 19.6 °C | 96.77 mm |
| June | 10.2 °C | 23.9 °C | 116.08 mm |
| July | 12.8 °C | 26.2 °C | 103.12 mm |
| August | 11.8 °C | 25.3 °C | 105.92 mm |
| September | 8.1 °C | 21.7 °C | 114.3 mm |
| October | 2.2 °C | 15 °C | 120.4 mm |
| November | -2.5 °C | 8.3 °C | 81.03 mm |
| December | -6.8 °C | 2.8 °C | 90.93 mm |
| Annual | 1 °C | 13.5 °C | 1152.66 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |