Groton, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.7 °C (low) to 13.5 °C (high). Annual precipitation averages 1102.6 Millimeters. Groton 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 | -9.9 °C | -0.6 °C | 68.07 mm |
| February | -9.3 °C | 0.7 °C | 56.9 mm |
| March | -5.4 °C | 4.9 °C | 75.18 mm |
| April | 0.9 °C | 12.4 °C | 93.98 mm |
| May | 7.2 °C | 19.6 °C | 91.19 mm |
| June | 12.3 °C | 24.2 °C | 118.62 mm |
| July | 14.8 °C | 26.6 °C | 106.93 mm |
| August | 13.9 °C | 25.9 °C | 109.47 mm |
| September | 9.9 °C | 22.2 °C | 106.17 mm |
| October | 4.2 °C | 15.1 °C | 105.66 mm |
| November | -0.8 °C | 8.3 °C | 90.42 mm |
| December | -5.7 °C | 2.3 °C | 80.01 mm |
| Annual | 2.7 °C | 13.5 °C | 1102.6 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |