Halong bay is located in the North of Vietnam. Therefore, it has a humid tropical climate and 4 seasons in a year. Winter lasts from December to March; temperature can drop down to 12°C-17°C. Summer is from May until September; It is sunny in this season however frequently heavy rains make the humidity high. Spring and Autumn are nice and warm, from October to early December is the best time to visit this area. If you want to visit Halong Bay, you should be aware that the weather is rather unpredictable and can vary greatly even within a day. So, the best time for outdoor activities is from April to November. However, the other months are still good enough for swimming and kayaking. For example, squid fishing is more efficient on foggy and rainny days and if you book our optional private boat for this activity, you will know why.