New London, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.1 °C (low) to 12.8 °C (high). Annual precipitation averages 863.1 Millimeters. New London is located in USDA Plant Hardiness Zone 5a. 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 | -12.5 °C | -3.6 °C | 34.29 mm |
| February | -11.4 °C | -1.5 °C | 30.73 mm |
| March | -5.7 °C | 4.8 °C | 48.51 mm |
| April | 0.9 °C | 12.5 °C | 82.55 mm |
| May | 7.7 °C | 19.7 °C | 98.3 mm |
| June | 13.4 °C | 25.1 °C | 118.87 mm |
| July | 15.6 °C | 27.4 °C | 101.35 mm |
| August | 14.6 °C | 26.4 °C | 96.01 mm |
| September | 9.9 °C | 22.4 °C | 85.6 mm |
| October | 3.5 °C | 14.7 °C | 74.68 mm |
| November | -2.6 °C | 6.6 °C | 46.99 mm |
| December | -8.8 °C | -0.6 °C | 45.21 mm |
| Annual | 2.1 °C | 12.8 °C | 863.09 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |