Oswegatchie, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.4 °C (low) to 12.4 °C (high). Annual precipitation averages 971.6 Millimeters. Oswegatchie is located in USDA Plant Hardiness Zone 4a. 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 | -12.6 °C | -3.2 °C | 73.66 mm |
| February | -12 °C | -1.8 °C | 59.94 mm |
| March | -6.2 °C | 3.2 °C | 63.5 mm |
| April | 1.3 °C | 11.6 °C | 81.28 mm |
| May | 7.9 °C | 19.1 °C | 81.03 mm |
| June | 13.2 °C | 23.9 °C | 89.92 mm |
| July | 15.9 °C | 26.6 °C | 91.44 mm |
| August | 14.8 °C | 25.9 °C | 84.58 mm |
| September | 10.4 °C | 21.9 °C | 88.9 mm |
| October | 4.6 °C | 14.2 °C | 98.55 mm |
| November | -1.2 °C | 7.3 °C | 79.25 mm |
| December | -7.7 °C | 0.4 °C | 79.5 mm |
| Annual | 2.4 °C | 12.4 °C | 971.55 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 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |