Halong is characterized by a tropical climate with hot and humid summers and dry winters. The rainy season in Halong runs from June to September, with the highest rainfall occurring in August.
When the rainy season starts, Halong becomes very hot and stuffy, the comfort level decreases, the humidity increases and it is not very pleasant to be in the city. The heavy rains that characterize this time of year are often not prolonged.
From September to October comes the so-called velvet season, when heavy precipitation stops and the air temperature is set at the optimum mark for a quality and pleasant vacation.