Lan Ha by month

What is the best month to go to Halong Bay and Lan Ha Bay?

April. Days reach about 27 C, the sea warms to about 23 C, rain is light and storms are rare. May, October and November are the next best.

April has the lot: the winter mist has gone, the summer storms haven't started, and the water is just warm enough for a swim stop. May is hotter (around 31 C) with warmer water and more afternoon showers. In October the sea is still about 28 C from the summer, the air cools to the high 20s and the storm risk drops fast.

For Lan Ha specifically, the shoulder months win twice. The beaches and lagoons it is known for are best in calm water, and a cancelled day costs more when you have already ridden 4 to 5 hours to Cat Ba. Late September is good value but still carries some storm risk.

What is Lan Ha Bay weather like month by month?

Cool and dry with morning fog from December to March, warm and clear in April and May, hot and stormy from June to September, then clear and mild in October and November.

Air and sea figures are weather2travel's Ha Long Bay averages (daytime highs); rain is the monthly average. Fog and storm notes come from cruise operators and our sources below.

Sources: weather2travel (temperatures, rain); Bai Tho Junks and Indochina Tour (fog, storms); Hai Phong city portal (June and July peak on Cat Ba); Rita cruise listing (1 October to 30 April peak).

When should you not visit Halong Bay?

July and August carry the highest storm risk, and the Tet week brings surcharges and sold-out transport. Summer weekends on Cat Ba are busy with domestic visitors.

Typhoons reach the Gulf of Tonkin mainly from July to September. Not every year brings a direct hit, but closures are routine: Quang Ninh kept Ha Long boats in port for Typhoon Wipha in July 2025 and Tapah in September 2025, Hai Phong closed the sea for Kajiki in August 2025, and both bays stopped for Storm Narra in August 2026. Typhoon Yagi in September 2024 hit Quang Ninh and Hai Phong hard.

Crowds are a separate problem. June and July are Cat Ba's domestic peak (the Hai Phong city portal counted about 1.6 million visitors in the first half of 2024, two-thirds of them Vietnamese), and the 30 April, 1 May and 2 September holidays fill the ferries. October to April is the international high season (the Rita cruise charges a peak supplement for exactly those months), and in the cold months the swim stops become look-but-don't-touch.

Is it always foggy in Halong Bay?

No. Fog is a winter thing, common on January and February mornings and lighter in March, and it usually lifts by 8:30 to 9:00.

Mist also turns up on some mornings in early February and mid-November, then burns off by mid-morning. A misty sunrise among the karsts is a look many people go for, and the afternoon sail is usually clear. From April to October fog is rare.

If views matter most, book a 2-day cruise rather than a day trip in winter: you get a second morning, and the odds that one of them is clear go up a lot.

What happens if a storm closes Lan Ha Bay?

The city suspends all sea activities, boats stay in port and tours are cancelled or rerouted; when the operator cancels for weather, the booking price is refunded.

Closures are ordered by the authorities, not chosen by crews. For Storm No. 5, Kajiki, Hai Phong suspended sea activities from 13:00 on 24 August 2025 and reopened at 10:00 on 26 August. For Storm Narra, DTiNews reported that Ha Long and Lan Ha tours and overnight stays were suspended from 7:00 on 22 August 2026 until conditions were safe.

• Operator cancels: GetYourGuide's terms say a supplier may cancel for adverse weather or government action, and the booking price is then refunded.
• Itinerary changes: cruise listings warn that routes can change at short notice for weather or tides; a cave may be swapped, not the whole trip.
• Your own cancellation: every tour on this site is free to cancel up to 24 hours before.
• Your bus, hotel and flights are separate bookings, so travel insurance is worth it from July to September.

If you want the ship to be the point, the Azura has a pool, spa and bay-view bathtub for days when the weather keeps everyone on board.

★ 4.9 · 2 to 3 days · from $179

Explore the 6-star Azura cruise → Tour details

When is Tet 2027 and what does it cost?

Lunar New Year falls on Saturday 6 February 2027; the proposed official break runs 4 to 10 February. Many boats add a surcharge for those dates.

Tuoi Tre reported the 6 February date and the ministry's backing for a seven-day break; the final schedule is set by the prime minister. Jungle Boss Tours notes that small restaurants and family shops close for the first three days, while hotels and the tourist strips stay open, and that trains and buses sold out weeks ahead for Tet 2026. Book transport early.

Surcharges we found on the listings, per person:

• Carnival 2-day cruise: $40 on 24 December, 31 December and Lunar New Year.
• Azura 6-star cruise: $5 at Tet.
• Hanoi day cruise: 150,000 VND from 5 to 8 February 2027.
• Rita 3-day cruise: $25 in peak season, 1 October to 30 April.
• The 2-day 5-star cruise adds an unstated surcharge on New Year, Christmas and national holidays.

Which month should you avoid in Hanoi?

June to August: Hanoi's hottest and wettest stretch, with highs around 34 C and the year's heaviest rain. Tet week is the other one to think about.

North-vietnam.com puts Hanoi's best months at March and April and September to November, and its worst at June to August. vietnamtourism.com adds that July and August are the most humid, around 80 to 85 percent, with flash flooding in some streets after heavy rain. The rainy season is also dengue season, so pack repellent.

Tet is different: the weather is fine, but many small businesses shut from 6 to 8 February 2027 while families celebrate. Hotels, chains and convenience stores stay open. If you want street food and markets, come a week either side.

What is the rainiest month in Vietnam's north?

August. Hanoi averages about 309 mm in August and Ha Long about 312 mm; July is close behind.

The Hanoi figure is the long-term average from the Vietnam Institute for Building Science and Technology; the Ha Long figure is weather2travel's. Summer rain in the north usually comes as afternoon downpours, roughly 14:00 to 17:00, rather than all-day grey, so a morning on the water often stays dry.

The rest of the country runs on a different clock. Central Vietnam's flood season peaks in October and November (vietnamtourism.com calls November the worst month for Hue and Hoi An), which is exactly when the north is at its best.

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