Lewis, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.3 °C (low) to 12 °C (high). Annual precipitation averages 833.1 Millimeters. Lewis is located in USDA Plant Hardiness Zone 4b. 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 | -16.2 °C | -5.7 °C | 21.84 mm |
| February | -14.4 °C | -2.6 °C | 22.61 mm |
| March | -7.4 °C | 4.4 °C | 40.39 mm |
| April | -0.4 °C | 12.3 °C | 72.14 mm |
| May | 6.7 °C | 19.9 °C | 98.3 mm |
| June | 12.2 °C | 24.9 °C | 114.05 mm |
| July | 14.7 °C | 27.3 °C | 106.17 mm |
| August | 13.4 °C | 26.2 °C | 108.2 mm |
| September | 9.1 °C | 21.7 °C | 88.14 mm |
| October | 2.4 °C | 13.8 °C | 81.53 mm |
| November | -4.7 °C | 4.5 °C | 47.75 mm |
| December | -11.8 °C | -2.7 °C | 32 mm |
| Annual | 0.3 °C | 12 °C | 833.12 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |