Hadley, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.3 °C (low) to 13.6 °C (high). Annual precipitation averages 1182.4 Millimeters. Hadley is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.6 °C | -1.1 °C | 88.14 mm |
| February | -10.9 °C | 0.6 °C | 71.63 mm |
| March | -5.8 °C | 5.3 °C | 95.5 mm |
| April | 0.8 °C | 13.3 °C | 103.38 mm |
| May | 7.4 °C | 20.2 °C | 97.79 mm |
| June | 12.4 °C | 24.5 °C | 120.65 mm |
| July | 15.3 °C | 27.1 °C | 105.41 mm |
| August | 14.3 °C | 26 °C | 103.12 mm |
| September | 10.2 °C | 22.1 °C | 87.63 mm |
| October | 3.8 °C | 15.1 °C | 114.05 mm |
| November | -1.7 °C | 7.9 °C | 92.2 mm |
| December | -7.1 °C | 1.8 °C | 102.87 mm |
| Annual | 2.3 °C | 13.6 °C | 1182.37 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 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 |