August in Waukesha averages a daily high of 26.8°C with nights around 15.5°C. Expect roughly 9.4 wet days totalling 105.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Waukesha is June–September.
Based on WAUKESHA WWTP, WI US (2.2km), 1995–2024. 20 years of August data.