Westbury, New York has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.7 °C (low) to 16.9 °C (high). Annual precipitation averages 1230.1 Millimeters. Westbury is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.6 °C | 4.3 °C | 96.27 mm |
| February | -2.9 °C | 5.7 °C | 78.23 mm |
| March | 0.4 °C | 9.6 °C | 110.74 mm |
| April | 5.5 °C | 15.7 °C | 102.87 mm |
| May | 10.8 °C | 21.1 °C | 98.55 mm |
| June | 16.1 °C | 26.1 °C | 110.24 mm |
| July | 19.4 °C | 29.1 °C | 104.39 mm |
| August | 18.8 °C | 28.2 °C | 111.51 mm |
| September | 15 °C | 24.6 °C | 103.38 mm |
| October | 8.9 °C | 18.5 °C | 118.87 mm |
| November | 3.8 °C | 12.5 °C | 85.6 mm |
| December | -0.3 °C | 7.3 °C | 109.47 mm |
| Annual | 7.7 °C | 16.9 °C | 1230.12 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |