Halong Bay Weather in September
September is a half/half month when the weather is no longer hot but not yet cold. It is an ideal time to visit Halong Bay.
September seems to be the transitional month from the blazing heat of summer to the more comfortable autumn. The average temperature drops to about 28oC with maximum temperature at noon is about 31oC and night temperature is as low as 25oC. The amount of rainfall though is still high at 328 mm; it is a significant decrease from July and August. The sea water temperature starts to cool down to 29oC.
√ Average temperature: 28oC
√ Average sea Temperature: 29oC
√ Monthly rainfall: 328mm
√ Average hours of sunshine per day: 6