Wauwatosa, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 14 °C (high). Annual precipitation averages 895.9 Millimeters. Wauwatosa is located in USDA Plant Hardiness Zone 6a. 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 | -9.8 °C | -1.4 °C | 43.18 mm |
| February | -8.2 °C | 0.6 °C | 42.42 mm |
| March | -3.2 °C | 6.4 °C | 50.29 mm |
| April | 2.5 °C | 13 °C | 100.08 mm |
| May | 8.5 °C | 19.6 °C | 99.57 mm |
| June | 14.1 °C | 25.2 °C | 120.9 mm |
| July | 17.2 °C | 28 °C | 91.44 mm |
| August | 16.5 °C | 27.2 °C | 92.71 mm |
| September | 12 °C | 23.3 °C | 80.77 mm |
| October | 5.6 °C | 16.2 °C | 70.36 mm |
| November | -0.7 °C | 8.3 °C | 52.83 mm |
| December | -6.3 °C | 1.6 °C | 51.31 mm |
| Annual | 4 °C | 14 °C | 895.86 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |