Halong's climate is humid and tropical. With a hot, humid summer and dry, cold winter; Halong’s temperature varies from 15ºC to 25ºC.
Annual rainfall is between 2000mm and 2200mm. Halong bay has typical diurnal tide system (tide amplitude ranges from 3.5-4m). The salinity is from 31 to 34.5MT in dry season and lower in rainy season.
The best time to travel
It is possible to visit Ha Long Bay year-round, with the best time to visit from October through April, although during the winter months of December, January and February, the weather can be cool and overcast with low visibility. During the summer months from May to September, temperatures rise and storms are more likely during the rainy season.