Andover, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.2 °C (low) to 13.6 °C (high). Annual precipitation averages 1005.6 Millimeters. Andover is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.1 °C | -0.3 °C | 66.8 mm |
| February | -9.9 °C | 0.9 °C | 48.01 mm |
| March | -6.5 °C | 5.6 °C | 70.1 mm |
| April | -0.6 °C | 13.1 °C | 84.84 mm |
| May | 5.4 °C | 20 °C | 90.68 mm |
| June | 10.3 °C | 24.3 °C | 105.92 mm |
| July | 12.6 °C | 26.5 °C | 100.58 mm |
| August | 11.7 °C | 25.7 °C | 96.77 mm |
| September | 7.9 °C | 21.9 °C | 97.54 mm |
| October | 2.4 °C | 15.1 °C | 96.01 mm |
| November | -2.4 °C | 8 °C | 76.45 mm |
| December | -6.7 °C | 2.2 °C | 71.88 mm |
| Annual | 1.2 °C | 13.6 °C | 1005.58 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |