April in Białystok averages a daily high of 13.6°C with nights around 1.7°C. Expect roughly 10.7 wet days totalling 36.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Białystok is May–September.
Based on BIALYSTOK, PL (3.7km), 1995–2024. 30 years of April data.