September in Haimen averages a daily high of 31.3°C with nights around 24.7°C. Expect roughly 8.8 wet days totalling 155.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Haimen is October–January.
Based on SHANTOU, CH (24.1km), 1995–2024. 14 years of September data.