September in Bolu averages a daily high of 25.2°C with nights around 11°C. Expect roughly 7.6 wet days totalling 28.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Bolu is June–October.
Based on BOLU, TU (0.6km), 1995–2024. 24 years of September data.