Greendale, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.6 °C (low) to 13.9 °C (high). Annual precipitation averages 934.5 Millimeters. Greendale 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.3 °C | -1.6 °C | 46.23 mm |
| February | -8.7 °C | 0.4 °C | 43.94 mm |
| March | -3.7 °C | 6.3 °C | 52.07 mm |
| April | 2.1 °C | 13.1 °C | 102.62 mm |
| May | 8.2 °C | 19.6 °C | 106.93 mm |
| June | 13.8 °C | 25.2 °C | 125.98 mm |
| July | 16.7 °C | 27.8 °C | 91.19 mm |
| August | 16.1 °C | 27.1 °C | 96.27 mm |
| September | 11.4 °C | 23.2 °C | 85.6 mm |
| October | 5.1 °C | 16.1 °C | 74.42 mm |
| November | -1.2 °C | 8.2 °C | 56.13 mm |
| December | -6.8 °C | 1.4 °C | 53.09 mm |
| Annual | 3.6 °C | 13.9 °C | 934.47 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |