Chestertown, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.9 °F (low) to 55.3 °F (high). Annual precipitation averages 44.3 Inches. Chestertown 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 9.1 °F | 29.1 °F | 3.3 in. |
| February | 10.2 °F | 31.9 °F | 2.62 in. |
| March | 19.4 °F | 40.2 °F | 3.49 in. |
| April | 30.6 °F | 54.3 °F | 3.83 in. |
| May | 43.3 °F | 67.4 °F | 3.77 in. |
| June | 52.4 °F | 75.7 °F | 4.51 in. |
| July | 57.8 °F | 80.2 °F | 4.11 in. |
| August | 56.0 °F | 78.2 °F | 3.7 in. |
| September | 48.3 °F | 70.9 °F | 3.46 in. |
| October | 36.8 °F | 57.5 °F | 4.24 in. |
| November | 26.7 °F | 44.5 °F | 3.42 in. |
| December | 16.7 °F | 33.7 °F | 3.85 in. |
| Annual | 33.9 °F | 55.3 °F | 44.3 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |