Orwell, 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 12.2 °C (high). Annual precipitation averages 1429.2 Millimeters. Orwell is located in USDA Plant Hardiness Zone 5a. 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 | -12.2 °C | -2.4 °C | 127 mm |
| February | -11.6 °C | -1.2 °C | 106.68 mm |
| March | -6.9 °C | 3.4 °C | 103.63 mm |
| April | 0 °C | 11.3 °C | 104.39 mm |
| May | 6.5 °C | 18.9 °C | 109.22 mm |
| June | 11.3 °C | 23.2 °C | 109.73 mm |
| July | 14.1 °C | 25.6 °C | 103.12 mm |
| August | 13.1 °C | 25.1 °C | 103.38 mm |
| September | 9.1 °C | 21.3 °C | 122.17 mm |
| October | 3.7 °C | 14.1 °C | 151.38 mm |
| November | -1.8 °C | 6.9 °C | 137.41 mm |
| December | -7.8 °C | 0.7 °C | 151.13 mm |
| Annual | 1.5 °C | 12.2 °C | 1429.24 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |