Any month works; each one asks for a different trade-off
Short answerNovember: about 6 rain days, 26°C by day, the sea at 25°C, no fog and the typhoon season ending. October and April come next. Every month works if you book with free cancellation; summer brings storm warnings, winter brings fog.
Tap a month
The bay has two seasons that pull in opposite directions. From May to October the sea is warm enough to swim, but that is also the rainy and typhoon season. From December to March the air is dry and cool, and fog settles on the karsts. The months in between, October, November and April, give the best of both.
Figure = average daytime high in °C; bar = rain days. Summer brings typhoon warnings, when ships return to port; winter brings fog on the karsts.
The figures are long-term averages for Ha Long city, where the ships sail from: daytime highs, rain days and the sea temperature. The wettest month is August, about 430 mm; the driest is December, about 18 mm.
Four seasons, one decision
The best time for a Halong Bay cruise depends on what you want from the bay: warm water, clear views or empty boats. The year falls into four seasons, and the same cruise feels different in each.
Our pick for most travellers is a one-night cruise between October and April, outside the holidays: sunset on deck, a night at anchor and the morning bay, without typhoon risk for most of those months.
Hanoi: 2-Day Ha Long, Lan Ha Bay 5-Star Cruise with BalconyEvery month in figures
Halong Bay cruise weather by month, as long-term averages. Temperatures are rounded to the nearest degree; a rain day is a day with measurable rain, often a short shower.
Two numbers matter most for a cruise. Rain days tell you how often a shower will interrupt the deck: from 5 in December to 19 in August. Typhoon risk tells you how likely it is that the boat does not sail at all: late May to early November, peak July–October.
December to February
A Halong Bay cruise in winter is dry and quiet. December is the driest month of the year, about 18 mm, and there is no typhoon risk from December to April. Daytime highs are 19–22°C, pleasant for the climb on Ti Top Island and the walk through Sung Sot Cave, which has stairs and takes 40 to 60 minutes.
The cost is fog. Heavy fog is possible from December to February, and in thick fog the Ha Long Bay Management Board can cancel tours. Nights on deck are cool, down to 14–15°C, so bring a warm layer. The sea, 19–22°C, is for kayaking rather than swimming.
Winter in practice
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May to September
A Halong Bay cruise in summer is about the water. The sea reaches 30°C in July and August, the swimming stops at Ti Top Island and the Lan Ha beaches are at their best, and the evenings on deck are long and warm. Days are hot, 30–32°C, and humid.
It is also the wet season: 16 to 19 rain days a month from June to August, mostly heavy showers, and the typhoon season, late May to early November, peak July–October. Summer is the busiest time too; the most booked day cruise warns on its listing that the bay is crowded from June to August and at weekends.
Summer in practice
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late May to early November, peak July–October
When a storm warning is issued, the Quang Ninh port authority stops issuing departure permits for tourist boats. Boats already at sea return to shore, and the ban lasts until the final storm bulletin. No operator can sail during a ban, whatever you booked.
For you this means a cancelled or shortened cruise, not a rough one. Every listing we read allows free cancellation up to 24 hours before departure and warns that the itinerary can change with the weather. From late May to early November, check the forecast two or three days ahead and keep the day after your cruise free.
How to book with free cancellationWhat happened and what changed
On 19 July 2025, at about 13:30, the day boat Vinh Xanh 58 (Wonder Sea) capsized in Ha Long Bay in a sudden severe thunderstorm and squall that forecasts had not flagged. It carried 49 people, 46 passengers and 3 crew; 39 died and 10 survived.
Quang Ninh province has since tightened the rules for every tourist boat:
Departure permits are still withheld whenever a storm warning is issued, as they were for Typhoon Ragasa in September 2025. When you board, ask the crew where the life jackets are kept.
Dates to check before you book
Christmas and New Year
Christmas Eve and New Year's Eve cost $40 more per person on the balcony cruises we read, often for a gala dinner.
Book early; the surcharge is on the listing, not in the price on our cards.
Lunar New Year
Tet carries a surcharge on many listings: $40 per person on the 2D1N luxury Ha Long and Lan Ha balcony cruise we read.
Check the listing before you pick a date around Tet.
30 April and 1 May
The national holidays carry a surcharge on many listings.
It is paid on the day; move a day either side if you can.
Summer weekends
The most booked day cruise warns that June to August and weekends are crowded.
Go on a weekday, or sail in Lan Ha.
Peak-season surcharge
The most reviewed Bai Tu Long cruise adds $10 per person from 1 October to 30 April.
It is paid on the day.
Fog days
In thick fog, usually December to February, tours can be cancelled.
Keep the free-cancellation option and a spare day.
What to book once you have a month
November. It has about 6 rain days, 26°C by day, a sea still at 25°C and no fog in the monthly averages, and the typhoon season is ending. October is the next best, warmer with a higher storm risk; December is the driest month but brings fog. Book with free cancellation whichever month you choose.
Yes, if you plan for it. From May to September the sea is warm, 28–30°C, and the islands are green, but it is the wettest part of the year, up to 430 mm in August, and typhoon warnings stop all tourist boats until they are lifted. Book with free cancellation and keep a spare day in Hanoi.
When a storm warning is issued, the Quang Ninh port authority stops issuing departure permits, boats at sea return to shore, and nothing sails until the final storm bulletin. The operator then moves you to another date or cancels. The listings we read also allow free cancellation up to 24 hours before departure, so you can cancel yourself when a storm is forecast.
Some people do, but few enjoy it. The sea is 19–22°C from December to February and the air at night falls to 14–15°C. Kayaking and the caves work well in winter; swimming stops at Ti Top Island are best from May to October, when the sea is above 28°C. A winter cruise still has the kayak or bamboo boat at Luon Cave.
Often. Heavy fog is possible from December to February, and March brings drizzle and haze, the dullest month of the year. In thick fog the Ha Long Bay Management Board can cancel tours. For clear views without the summer storms, aim for October, November or April, when fog is rare in the averages.
Since the capsizing of July 2025, Quang Ninh has announced an early-warning system for thunderstorms and squalls, required about 500 tourist boats to carry AIS, VHF radio and GPS, put a medical vessel and two rescue boats on patrol day and night, and started surprise inspections of boats and ports. Departure permits are still stopped whenever a storm warning is issued.
In summer, June to August, and at weekends, as the most booked day cruise warns on its listing; national holidays such as the Lunar New Year and 30 April to 1 May also carry surcharges. Outside summer, a weekday is the quieter choice on the classic route. For fewer boats in any month, choose Lan Ha or Bai Tu Long Bay.
Christmas Eve, New Year's Eve and the Lunar New Year carry a surcharge on most listings: $40 per person on the balcony cruises we read, often for a gala dinner. National holidays add a surcharge on some ships. The most reviewed Bai Tu Long cruise also adds $10 per person in its peak season, 1 October to 30 April, paid on the day.
November, one night, free cancellation
Hanoi: 2-Day Ha Long, Lan Ha Bay 5-Star Cruise with BalconyPickup: Hanoi Old Quarter · transfer $25 extra
