April in Basel averages a daily high of 16.3°C with nights around 5.5°C. Expect roughly 11.3 wet days totalling 62.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Basel is June–September.
Based on BASEL BINNINGEN, SZ (2.9km), 1995–2024. 30 years of April data.