Lake Mills, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.6 °F (low) to 56.8 °F (high). Annual precipitation averages 37.1 Inches. Lake Mills is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.3 °F | 27.1 °F | 1.49 in. |
| February | 14.1 °F | 30.9 °F | 1.48 in. |
| March | 24.6 °F | 43.0 °F | 2.08 in. |
| April | 35.9 °F | 56.6 °F | 3.81 in. |
| May | 47.6 °F | 69.1 °F | 4.04 in. |
| June | 57.7 °F | 78.9 °F | 5.38 in. |
| July | 61.8 °F | 82.5 °F | 4.28 in. |
| August | 59.8 °F | 80.5 °F | 4.26 in. |
| September | 51.5 °F | 73.9 °F | 3.49 in. |
| October | 40.0 °F | 60.5 °F | 2.91 in. |
| November | 28.7 °F | 45.5 °F | 2.13 in. |
| December | 18.2 °F | 32.6 °F | 1.76 in. |
| Annual | 37.6 °F | 56.8 °F | 37.11 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |