Quick answer: The best time to visit Halong Bay is October–November and March–May: mostly dry, 20–30°C and calm seas for cruising. June–August is hot, wet and busy, with the odd storm. December–February is cool and misty – no beach weather, but beautifully moody and usually cheaper outside Tet.
People always ask me for the “perfect” month. Truth is, Halong is beautiful all year – it just changes personality. In winter the limestone islands fade in and out of the mist like an old ink painting. In summer the water turns bright jade and you’ll want to jump off the boat. What matters is matching the season to what you want to do.
What is the weather like in Halong Bay each month?
| Month | Low / High (°C) | Rain (mm) | Sea (°C) | Simon’s verdict |
|---|---|---|---|---|
| January | 14 / 19 | 25 | 21.5 | Cool, misty, quiet |
| February | 15 / 20 | 25 | 21 | Drizzly, Tet crowds |
| March | 18 / 22 | 40 | 22 | Mild, some haze |
| April | 21.5 / 26 | 90 | 24 | Great for cruising |
| May | 24.5 / 30 | 170 | 27.5 | Warm, first swims |
| June | 26 / 31.5 | 300 | 29.5 | Hot, showers |
| July | 26 / 31.5 | 325 | 30 | Peak storm risk |
| August | 25.5 / 31 | 445 | 30 | Wettest month |
| September | 24.5 / 30.5 | 280 | 29.5 | Warm, still stormy |
| October | 22 / 29 | 160 | 28 | My favourite |
| November | 18.5 / 25.5 | 35 | 25.5 | Dry, clear, lovely |
| December | 15.5 / 21.5 | 20 | 23 | Chilly evenings |
Long-term climate averages – real days can be warmer or cooler.
Halong Bay seasons explained
Spring (March – May): the all-rounder
Temperatures climb from about 18°C to 30°C and rain stays light until mid-May. Visibility improves after the March haze, so April and May are excellent for cruising, kayaking and hiking on Cat Ba Island.
Summer (June – August): hot, green and busy on weekends
Expect 30–32°C, high humidity and short, heavy showers. The sea is at its warmest (around 30°C) – the best time for swimming. This is peak season for Vietnamese families, so weekends are crowded, while weekdays can still be quiet. August is the wettest month.
Autumn (September – November): clear skies and calm water
Storm risk fades through October, humidity drops and the light is sharp for photos. October and November are my favourite months on the bay – and the busiest for international visitors, so book 2–4 weeks ahead.
Winter (December – February): misty, quiet and good value
Around 14–20°C, often grey with light drizzle. Too cool for most swimmers, but perfect for cave visits and slow mornings on deck with a hot drink. Prices are usually softer – except during Tet.
When is typhoon season in Halong Bay?
Storms can hit from late May to early November, most often July to October. When there’s a storm warning, the local authorities stop cruise boats from leaving the harbour – safety first, no arguing with that. My advice: book with an operator that lets you move your date, and don’t plan your cruise for the day before your international flight.
Crowds and prices: busy vs quiet times
- Busiest: Saturdays all year, Tet (late January/February), 30 April – 1 May, June–August (domestic holidays) and October–November (international peak).
- Quietest and best value: weekdays in December and early January, late February–March (after Tet) and weekdays in September.
- Typical 2-day / 1-night cruise, per person: roughly $60–$150 for standard boats, $150–$300 for premium and up to $500 for luxury cruises.
Festivals worth planning around
- Tet (Lunar New Year) – late January or February. A festive time, but many locals travel: book early and expect higher prices.
- Yen Tu Festival – opens after Tet and runs into spring. Pilgrims climb Yen Tu Mountain, about an hour from Halong; easy to combine with a cruise.
- Halong Carnival – when it is held, usually around late April or early May, with street parades and fireworks. Check the local events calendar before you book around it.
Can you swim in Halong Bay?
Yes – from about May to October the sea sits at 27–30°C, perfect for a swim off the boat or at Ti Top beach. In winter the water drops to around 21°C. Some guests still jump in; most just watch and hold the camera.
What to pack by season
- Spring / autumn: light layers, comfortable shoes, a light rain jacket.
- Summer: sunscreen, swimwear, sunglasses, a hat and plenty of water.
- Winter: a warm jacket or windbreaker for the sundeck, especially mornings and evenings.
A local guide’s tips for the best experience
- Avoid weekends and Vietnamese holidays if you can – domestic tourists flood the bay on Saturdays and during Tet and 30 April – 1 May.
- Want fewer boats? Ask about routes through Lan Ha Bay or Bai Tu Long Bay – same scenery, far less traffic.
- Kayaking is best on calm mornings; the water is usually flattest before lunch.
- Sunrise from the top deck beats sunset – set an alarm, it’s worth it.
FAQ
What is the best month to visit Halong Bay?
October and November for clear skies and calm seas; April and May are a close second.
Do cruises run in the rainy season?
Yes, most days. They’re only cancelled when the authorities issue a storm warning.
Is Halong Bay cold in winter?
Cool rather than cold – around 14–20°C, chilly on deck at night.
When is the cheapest time to visit Halong Bay?
Weekdays from December to early January, and just after Tet, when cruises are quieter and discounts are common.
How many days do I need?
A 2-day, 1-night cruise is the sweet spot for most travellers.
Plan your trip with a local: see our Ninh Binh – Halong – Sapa 5D4N Tour or Hanoi – Ninh Binh – Halong 5D4N Tour, or message us and we’ll pick the right cruise for your dates. Browse all Halong Bay tours.
