April in Bolu averages a daily high of 17.1°C with nights around 4.1°C. Expect roughly 12.4 wet days totalling 50.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bolu is June–October.
Based on BOLU, TU (0.6km), 1995–2024. 27 years of April data.