Andover, New Jersey has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.7 °C (low) to 15.8 °C (high). Annual precipitation averages 1229.6 Millimeters. Andover is located in USDA Plant Hardiness Zone 6b. 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 | -7.7 °C | 2.2 °C | 87.63 mm |
| February | -6.8 °C | 3.8 °C | 70.36 mm |
| March | -2.6 °C | 8.4 °C | 100.33 mm |
| April | 3.7 °C | 15.4 °C | 91.69 mm |
| May | 9.2 °C | 21.2 °C | 101.85 mm |
| June | 14.4 °C | 25.9 °C | 126.75 mm |
| July | 16.9 °C | 28.7 °C | 107.95 mm |
| August | 16.1 °C | 27.6 °C | 120.9 mm |
| September | 11.8 °C | 23.8 °C | 117.6 mm |
| October | 5.5 °C | 17.2 °C | 115.06 mm |
| November | 0.1 °C | 10.9 °C | 87.12 mm |
| December | -4.1 °C | 4.9 °C | 102.36 mm |
| Annual | 4.7 °C | 15.8 °C | 1229.6 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |