September in Appleton averages a daily high of 22.5°C with nights around 10.8°C. Expect roughly 9.3 wet days totalling 76.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Appleton is May–September.
Based on APPLETON, WI US (2.4km), 1995–2024. 30 years of September data.