Greendale, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.4 °F (low) to 57 °F (high). Annual precipitation averages 36.8 Inches. 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 | 13.5 °F | 29.2 °F | 1.82 in. |
| February | 16.4 °F | 32.8 °F | 1.73 in. |
| March | 25.4 °F | 43.3 °F | 2.05 in. |
| April | 35.8 °F | 55.5 °F | 4.04 in. |
| May | 46.7 °F | 67.3 °F | 4.21 in. |
| June | 56.8 °F | 77.3 °F | 4.96 in. |
| July | 62.1 °F | 82.0 °F | 3.59 in. |
| August | 60.9 °F | 80.7 °F | 3.79 in. |
| September | 52.6 °F | 73.7 °F | 3.37 in. |
| October | 41.1 °F | 60.9 °F | 2.93 in. |
| November | 29.9 °F | 46.7 °F | 2.21 in. |
| December | 19.8 °F | 34.5 °F | 2.09 in. |
| Annual | 38.4 °F | 57 °F | 36.79 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |