Hemlock, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.5 °C (low) to 14.1 °C (high). Annual precipitation averages 941.3 Millimeters. Hemlock is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.7 °C | 0.3 °C | 56.39 mm |
| February | -8.5 °C | 1.3 °C | 45.97 mm |
| March | -4.6 °C | 5.9 °C | 67.56 mm |
| April | 1.3 °C | 13.2 °C | 78.23 mm |
| May | 7.7 °C | 20.1 °C | 81.79 mm |
| June | 12.9 °C | 24.6 °C | 99.57 mm |
| July | 15.4 °C | 26.8 °C | 105.66 mm |
| August | 14.7 °C | 26.1 °C | 91.95 mm |
| September | 10.9 °C | 22.6 °C | 88.14 mm |
| October | 5.3 °C | 15.7 °C | 93.22 mm |
| November | 0.1 °C | 9 °C | 69.85 mm |
| December | -4.8 °C | 3.2 °C | 62.99 mm |
| Annual | 3.5 °C | 14.1 °C | 941.32 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |