April in Oshkosh averages a daily high of 12.6°C with nights around 2.3°C. Expect roughly 11.8 wet days totalling 78.8mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Oshkosh is May–September.
Based on OSHKOSH, WI US (1.3km), 1995–2024. 30 years of April data.