Hornell, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.5 °F (low) to 57.4 °F (high). Annual precipitation averages 36.8 Inches. Hornell 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.6 °F | 32.1 °F | 2.27 in. |
| February | 15.0 °F | 34.5 °F | 1.87 in. |
| March | 21.7 °F | 42.5 °F | 2.5 in. |
| April | 32.3 °F | 56.0 °F | 3.15 in. |
| May | 42.9 °F | 68.5 °F | 3.35 in. |
| June | 52.1 °F | 76.9 °F | 3.93 in. |
| July | 56.3 °F | 81.1 °F | 3.67 in. |
| August | 54.8 °F | 79.6 °F | 3.74 in. |
| September | 48.2 °F | 72.8 °F | 3.64 in. |
| October | 38.1 °F | 59.8 °F | 3.58 in. |
| November | 29.2 °F | 47.4 °F | 2.62 in. |
| December | 21.1 °F | 37.1 °F | 2.43 in. |
| Annual | 35.5 °F | 57.4 °F | 36.75 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |