Westmoreland, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.2 °C (low) to 13.8 °C (high). Annual precipitation averages 1172.7 Millimeters. Westmoreland 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | -1.1 °C | 80.01 mm |
| February | -9.9 °C | 0.2 °C | 74.17 mm |
| March | -5.1 °C | 4.8 °C | 82.04 mm |
| April | 1.4 °C | 13 °C | 93.22 mm |
| May | 7.7 °C | 20.4 °C | 97.79 mm |
| June | 13.2 °C | 25 °C | 124.71 mm |
| July | 15.9 °C | 27.6 °C | 103.12 mm |
| August | 15.1 °C | 26.6 °C | 103.12 mm |
| September | 11 °C | 22.7 °C | 101.85 mm |
| October | 5.1 °C | 15.3 °C | 120.9 mm |
| November | -0.3 °C | 8.4 °C | 96.27 mm |
| December | -5.7 °C | 2.1 °C | 95.5 mm |
| Annual | 3.2 °C | 13.8 °C | 1172.7 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |