Onalaska, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.2 °C (low) to 13.8 °C (high). Annual precipitation averages 932.9 Millimeters. Onalaska is located in USDA Plant Hardiness Zone 5a. 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 | -12.5 °C | -3.2 °C | 29.72 mm |
| February | -10.6 °C | -0.6 °C | 29.46 mm |
| March | -4.2 °C | 6.2 °C | 50.8 mm |
| April | 2.8 °C | 14.2 °C | 101.09 mm |
| May | 9.3 °C | 21.1 °C | 121.16 mm |
| June | 15 °C | 26.4 °C | 132.84 mm |
| July | 17.2 °C | 28.4 °C | 108.71 mm |
| August | 16.1 °C | 27.4 °C | 104.65 mm |
| September | 11.4 °C | 23.2 °C | 96.77 mm |
| October | 4.7 °C | 15.7 °C | 71.37 mm |
| November | -1.9 °C | 6.9 °C | 48.77 mm |
| December | -8.5 °C | -0.3 °C | 37.59 mm |
| Annual | 3.2 °C | 13.8 °C | 932.93 mm |
| 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |