Lake Delton, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.7 °F (low) to 56.1 °F (high). Annual precipitation averages 36.9 Inches. 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 | 8.9 °F | 26.4 °F | 1.24 in. |
| February | 11.5 °F | 30.6 °F | 1.3 in. |
| March | 22.4 °F | 42.8 °F | 2.14 in. |
| April | 34.0 °F | 56.3 °F | 4.1 in. |
| May | 46.2 °F | 68.5 °F | 4.31 in. |
| June | 56.4 °F | 78.0 °F | 5.25 in. |
| July | 60.3 °F | 81.9 °F | 4.08 in. |
| August | 58.0 °F | 80.0 °F | 4.16 in. |
| September | 49.7 °F | 72.7 °F | 3.72 in. |
| October | 38.0 °F | 59.4 °F | 2.93 in. |
| November | 26.8 °F | 44.5 °F | 1.98 in. |
| December | 16.0 °F | 31.8 °F | 1.73 in. |
| Annual | 35.7 °F | 56.1 °F | 36.94 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |