Halong Bay Weather, Best time to visit

Halong Bay Vietnam has a tropical monsoon climate: summer from May through July, autumn from late August through October, winter from November through February, spring from February through April.

 From June through October or sometimes November, Halong Bay may be affected by tropical depressions or typhoons. During the time that Halong Bay may be affected by a tropical storm, or typhoon, or tropical depression, cruises on the bay are prohibited.Sunset on Halong Bay Vietnam

The monsoons which influence Halong Bay include the northeasterly monsoon in the winter and the southeasterly monsoon in the summer. Part of the northeasterly monsoon blows along the coast from Siberia, China… which is quite moist and it often causes drizzles on Halong Bay when it first arrives.

Halong Bay may be foggy when the warm and moist sea water evaporates into the cool air or when the warm moist wind blows on a cool sea water surface. In late March and early April, there are often times when the two moist monsoons both blow on Halong Bay weakly and the several mountains on Halong Bay block the winds effectively making the air still. Fogs are often worst during these times.

Halong Bay’s weather by month
- January: Relatively dry, light rains, 6-24oC
- February: cold and relatively dry, possible light rains, 11-27oC
- March: fairly cool and dry, possible light rains and fogs, 15-30oC
- April: mostly dry and pleasant, possible fog in the first half of the month, 19-31oC
- May: Rains and thunderstorms sometimes, 23-29oC mostly.
- June: sun and thunderstorms, 24-32oC.
- July: Sun, thunderstorms, 28-33oC
- August
- September
- October
- November
- December

The best time for nice weather to visit Halong Bay
It is hard to say when it is best to visit Halong Bay as it depends on individual preferences and chances of bad weather during each period of the year on the bay.

If you like dry weather free of tropical storms, long lasting rains, thick fog; you may like to have a cruise on Halong Bay in late April and May. The temperatures may be high during this period and there may be occasional thunderstorms with rains for a couple of hours each only.

If you like bright sun and clear skies on Halong Bay, then a trip on the bay should be done between May and July. But there are chances that there may often be a couple of typhoons or tropical depressions each year during this period that cruises on Halong Bay are forbidden.

Halong Bay on a clear day with blue sky and bright sunshine
Halong Bay on a clear day with blue sky and bright sunshine

From August through October, it is autumn in Halong Bay and northern Vietnam, the best season for lovely photography on Halong Bay: soft light, thin mist, blue skies… which help to make your photographs great. The temperatures are lovely during this time, and along with relatively low humidity it makes the air very pleasant. The cons are that there a a few tropical depressions or typhoons which affect Halong Bay during this period. Each time a typhoon is about to come to northern Vietnam, cruises on Halong Bay are forbidden at least 1 day before its arrival or its making landfall.

From November to early February, it is winter in Halong Bay. It could be anything from lovely clear sky with weak sunshine, or gloomy cold with strong cold wind or gloomy and cold and wet because of long-lasting drizzles.

From later February through March, it is spring time in Halong Bay. There are a few days often at the end of March and early April that it is very foggy on the bay. The temperatures are often pleasant during this time.