South Milwaukee, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.7 °F (low) to 55.8 °F (high). Annual precipitation averages 36.6 Inches. South Milwaukee 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.0 °F | 30.0 °F | 1.83 in. |
| February | 18.8 °F | 32.9 °F | 1.73 in. |
| March | 27.5 °F | 42.4 °F | 2.14 in. |
| April | 37.3 °F | 52.5 °F | 4.26 in. |
| May | 47.4 °F | 63.8 °F | 4.27 in. |
| June | 57.9 °F | 74.1 °F | 4.6 in. |
| July | 64.4 °F | 79.9 °F | 3.44 in. |
| August | 64.0 °F | 78.8 °F | 3.67 in. |
| September | 56.1 °F | 72.2 °F | 3.24 in. |
| October | 44.2 °F | 60.0 °F | 3.11 in. |
| November | 32.7 °F | 47.1 °F | 2.33 in. |
| December | 22.2 °F | 35.3 °F | 1.98 in. |
| Annual | 40.7 °F | 55.8 °F | 36.6 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |