Delevan, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.6 °F (low) to 55.8 °F (high). Annual precipitation averages 46.2 Inches. Delevan 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 | 14.0 °F | 30.5 °F | 3.59 in. |
| February | 14.3 °F | 32.8 °F | 2.69 in. |
| March | 21.0 °F | 41.1 °F | 3.04 in. |
| April | 32.2 °F | 54.6 °F | 3.59 in. |
| May | 43.5 °F | 67.0 °F | 3.83 in. |
| June | 52.5 °F | 74.9 °F | 4.52 in. |
| July | 56.7 °F | 78.9 °F | 4.41 in. |
| August | 54.8 °F | 78.0 °F | 4.22 in. |
| September | 48.6 °F | 71.3 °F | 4.29 in. |
| October | 38.4 °F | 59.1 °F | 4.2 in. |
| November | 29.4 °F | 46.1 °F | 3.88 in. |
| December | 21.3 °F | 35.7 °F | 3.93 in. |
| Annual | 35.6 °F | 55.8 °F | 46.19 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |