Halong Bay Weather by Month 2027, and When Cruises Stop

Halong Bay weather is best from late October to early December: highs of 22°C to 29°C, under 145 mm of rain a month. Summer is hot and wet, and from June to October storms stop every cruise for a day or two at a time. January to April is cool and often grey, with fog that flattens the views.

Halong Bay weather by month

Air, rain and sun are long-term averages for Bai Chay station in Ha Long city, from Vietnam's climate standard QCVN 02:2022/BXD. Sea temperatures are from weather2travel.

August takes 431 mm of rain, nearly a quarter of the year's 1,923 mm. March has the most rain days of the dry half, 14, yet only 43 mm falls: that is drizzle and mist, not storms. The QCVN 02:2022 climate tables have the decimals. For the rest of the country that month, see Vietnam weather in August.

The best time to visit Halong Bay for weather

November is the safest month. Rain drops to 39 mm over six days, afternoons reach 26°C and the sea is still 25°C. October is warmer, with a 28°C sea and 177 hours of sun, but the storm season is not over: Typhoon Matmo stopped every tourist boat in the bay on 5 October 2025. If you can only fit one night on the water, a Halong Bay 2 day 1 night cruise in November is the one least likely to be called off.

December is drier still, at 18 mm, but the northeast monsoon brings 15°C nights and a 22°C sea few people swim in.

April and May are the second window. The fog lifts, the sea warms to 23°C and then 27°C, and May's 183 mm falls mostly in short afternoon showers. For how Halong fits the rest of the country, see the best time to visit Vietnam.

Fog and grey skies from February to April

Bai Chay averages 48 hours of sun in February and 43 in March, under two hours a day. Humidity sits around 87% in March, the highest of the year, and sea mist often hangs between the islands until late morning.

February and March average under two hours of sun a day.

Cruises still sail. The problem is visibility: the karsts fade to grey shapes and the long views disappear. If you only have one shot at Halong, move it to April or November.

Storm season and cruise cancellations

Storms reach the Gulf of Tonkin from June to October, with August and September the riskiest months. When a storm is forecast, the decision is not the cruise company's. Quang Ninh's inland waterway port authority stops issuing departure permits for tourist boats, and nobody sails until the ban is lifted. If your cruise falls in September, Vietnam weather in September shows where the rest of the trip stays drier.

Thunderstorms build fast in the summer months.

How often? These are the 2025 stoppages, from Ha Long Bay Management Board notices and Vietnamese press reports.

Six stoppages in under four months, about one every three weeks. Most lasted one to three days. The Wipha ban, reported by Tuoi Tre News on 20 July, was expected to hold until at least the 22nd. In summer, plan to lose a day.

The rules tightened after the worst accident in the bay's tourist history. At about 1:30 pm on 19 July 2025 the day boat Vinh Xanh 58 capsized in a sudden storm near Dau Go Cave with 49 people on board. Three days later 37 were confirmed dead and two were still missing, VnExpress reported. Since then every tourist boat has been inspected and bad-weather departure checks are stricter.

How refunds work

No law sets the refund; the company's terms do, and the larger operators publish similar ones. If the authorities cancel before you leave Hanoi, you get a full refund or a new date. Once you are at the harbour, what you have used, usually the transfer and lunch, is deducted. The call often comes around 3 pm on the departure day.

The awkward part: cancel yourself over a bad forecast while the boats are still allowed out, and normal cancellation terms apply. Close to departure that can mean no refund at all. Read the weather clause before paying the deposit.

Our Halong Bay cruise guide compares one-, two- and three-day trips, from about USD 55 to 500 per person.

Swimming and kayaking: the warm-water months

The sea is 27°C to 30°C from May to October and 19°C to 20°C from January to March. Most cruises include a kayak or bamboo-boat stop; in cold months some swap the swim for a cave walk.

Kayaking under a rock arch in Halong Bay.

For kayaking with the fewest weather risks, aim for late October or early November: a 28°C then 25°C sea, and only nine and six rain days. Summer water is warmer, but afternoon thunderstorms clear the kayaks off it fast.

Halong or Lan Ha in bad weather

The weather is the same. Lan Ha, off Cat Ba Island just south of Halong, shares its monsoon, fog and typhoons. What differs is the authority. Halong cruises leave mostly from Tuan Chau near Ha Long city, under Quang Ninh permits. Lan Ha boats leave from Cat Ba or Got pier under Hai Phong's, so a ban in one bay does not always close the other the same day. A real typhoon closes both: Wipha cancelled cruises in Ha Long and Lan Ha alike.

Lan Ha also has fewer boats spread over more anchorages, so a grey day there feels less crowded. Our Lan Ha Bay vs Halong Bay comparison covers price and routes, and Sapa or Halong Bay helps if you are choosing between the bay and the mountains.

Floating fish farms in Lan Ha Bay, which falls under Hai Phong, not Quang Ninh.

Getting there, and keeping a spare day

Ha Long is about 165 km from central Hanoi, around 2.5 to 3 hours by expressway. Our Hanoi to Halong Bay transport guide compares the limousine vans, buses and Grab.

From June to October, keep one free day in Hanoi between the cruise and an international flight, and check the national weather service three days ahead.

The boat station for Phong Nha Cave on the Son River.

Heading south to Phong Nha

Phong Nha is about 510 km south of Ha Long by road, around 10 hours by direct sleeper bus to Dong Hoi. Our Halong Bay to Phong Nha itinerary has the timings.

Phong Nha's dry stretch runs from about February to August, under 170 mm of rain a month at Dong Hoi, which covers most of Halong's wet months. The one-day Elephant Cave and Ma Da Valley trek costs VND 1,950,000, about US$74 (November 2026). It runs daily with pickup around 8:00 AM, takes children from 9, and ends with a 600 m swim into Tra Ang cave.