Harpersfield, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.5 °C (low) to 12.8 °C (high). Annual precipitation averages 1142.2 Millimeters. Harpersfield is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.6 °C | -0.8 °C | 74.42 mm |
| February | -10.2 °C | 0.3 °C | 60.96 mm |
| March | -6.1 °C | 5.1 °C | 81.79 mm |
| April | -0.3 °C | 12.3 °C | 97.28 mm |
| May | 5.2 °C | 19 °C | 98.81 mm |
| June | 10.7 °C | 23 °C | 112.27 mm |
| July | 13.2 °C | 25.3 °C | 113.79 mm |
| August | 12.5 °C | 24.7 °C | 112.78 mm |
| September | 8.9 °C | 21.2 °C | 101.85 mm |
| October | 3.5 °C | 14.6 °C | 109.98 mm |
| November | -2 °C | 7.4 °C | 90.68 mm |
| December | -6.5 °C | 1.8 °C | 87.63 mm |
| Annual | 1.5 °C | 12.8 °C | 1142.24 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| 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 |