Lake Delton, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2 °C (low) to 13.4 °C (high). Annual precipitation averages 938.3 Millimeters. Lake Delton is located in USDA Plant Hardiness Zone 5a. 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 | -12.8 °C | -3.1 °C | 31.5 mm |
| February | -11.4 °C | -0.8 °C | 33.02 mm |
| March | -5.3 °C | 6 °C | 54.36 mm |
| April | 1.1 °C | 13.5 °C | 104.14 mm |
| May | 7.9 °C | 20.3 °C | 109.47 mm |
| June | 13.6 °C | 25.6 °C | 133.35 mm |
| July | 15.7 °C | 27.7 °C | 103.63 mm |
| August | 14.4 °C | 26.7 °C | 105.66 mm |
| September | 9.8 °C | 22.6 °C | 94.49 mm |
| October | 3.3 °C | 15.2 °C | 74.42 mm |
| November | -2.9 °C | 6.9 °C | 50.29 mm |
| December | -8.9 °C | -0.1 °C | 43.94 mm |
| Annual | 2 °C | 13.4 °C | 938.27 mm |
| 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 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 |