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. It is possible to visit Halong 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.
  • March  April + May: Temperature: ~ 20°F-22°F; Some day have light rain; Clear with blue sky
  • June + July + Aug:  Temperature: ~ 26°F-28°F with strong Sun; Carefully with Typhoon; Some day have trong rain but quick 
  • Sept + Oct + Nov: Best time to enjoy Halong with cool temperature: ~ 26°F-28°F
  • Dec + Jan + Feb: Temperature: 18°F~20°F; Cold with strong wind; Some day is misty and rainy


Best time to travel Halong Bay

All year around will be fine, but check Typhoon forecast before you go
The best time to visit Halong Bay from Sept and October ; March and April