Greenwich, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.5 °C (low) to 14.5 °C (high). Annual precipitation averages 1117.9 Millimeters. Greenwich is located in USDA Plant Hardiness Zone 5b. 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 | -11 °C | -0.3 °C | 79.5 mm |
| February | -10.5 °C | 1.4 °C | 58.67 mm |
| March | -5.3 °C | 6.4 °C | 80.01 mm |
| April | 1.4 °C | 14.3 °C | 88.65 mm |
| May | 7.6 °C | 21 °C | 93.73 mm |
| June | 12.7 °C | 25.3 °C | 121.16 mm |
| July | 15 °C | 28.1 °C | 106.68 mm |
| August | 14.3 °C | 27.1 °C | 114.3 mm |
| September | 9.9 °C | 23.2 °C | 100.58 mm |
| October | 3.9 °C | 16.1 °C | 104.65 mm |
| November | -1.4 °C | 9.1 °C | 84.33 mm |
| December | -6.4 °C | 2.7 °C | 85.6 mm |
| Annual | 2.5 °C | 14.5 °C | 1117.86 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 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 |