Brown Deer, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 13.8 °C (high). Annual precipitation averages 891.3 Millimeters. Brown Deer 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 | -9.6 °C | -1.4 °C | 43.18 mm |
| February | -8.1 °C | 0.5 °C | 41.66 mm |
| March | -3.2 °C | 6.2 °C | 51.05 mm |
| April | 2.3 °C | 12.8 °C | 102.11 mm |
| May | 8.2 °C | 19.4 °C | 100.08 mm |
| June | 13.8 °C | 24.9 °C | 113.79 mm |
| July | 16.9 °C | 27.7 °C | 90.17 mm |
| August | 16.4 °C | 26.8 °C | 90.68 mm |
| September | 12.1 °C | 23.1 °C | 82.04 mm |
| October | 5.7 °C | 16.1 °C | 72.39 mm |
| November | -0.6 °C | 8.2 °C | 52.83 mm |
| December | -6.1 °C | 1.7 °C | 51.31 mm |
| Annual | 4 °C | 13.8 °C | 891.29 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 |