Grahamsville, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.1 °C (low) to 14.5 °C (high). Annual precipitation averages 1276.9 Millimeters. Grahamsville 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | 0.4 °C | 87.12 mm |
| February | -8.5 °C | 2.2 °C | 70.87 mm |
| March | -4.2 °C | 6.7 °C | 91.19 mm |
| April | 1.7 °C | 14.2 °C | 91.69 mm |
| May | 7.4 °C | 20.3 °C | 106.43 mm |
| June | 12.6 °C | 24.9 °C | 131.57 mm |
| July | 15.2 °C | 27.6 °C | 133.35 mm |
| August | 14.2 °C | 26.5 °C | 114.55 mm |
| September | 10.3 °C | 22.6 °C | 125.98 mm |
| October | 4.1 °C | 15.8 °C | 123.95 mm |
| November | -1.1 °C | 9.2 °C | 95.25 mm |
| December | -5.7 °C | 3.1 °C | 104.9 mm |
| Annual | 3.1 °C | 14.5 °C | 1276.85 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |