September in Ostend averages a daily high of 19.4°C with nights around 13.7°C. Expect roughly 12 wet days totalling 62.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Ostend is June–September.
Based on WEST SOUBURG, NL (53.5km), 1995–2024. 30 years of September data.