The climate of the bay is tropical, wet, sea islands, with two seasons: hot and moist summer, and dry and cold winter. The average temperature is from 15°C- 25°C, and annual rainfall is between 2000mm and 2200mm. Hạ Long Bay has the typical diurnal tide system (tide amplitude ranges from 3.5-4m). The salinity is from 31 to 34.5MT in the dry season and lower in the rainy season
