Can you swim in Halong Bay in winter? December to February, honestly

The short answer

Can you swim in Halong Bay in winter? Our own weather guide puts warm water for swimming at May to September. It also says December to February is quieter, with the island often wrapped in fog or rain. One sea-temperature site gives a January average of 19.4°C. Vietnam's tourism board calls the bay cool to cold and misty from December to March. Whether your ship runs a swim or kayak stop on your date is not in our data, so ask us and we confirm it.

We are a family on Cat Ba, and we sell places on the ships below and on our own small boat. We have no winter swimming stories from guests to share. This guide is compiled from sources we cross-checked, and every number is labelled with where it comes from.

Water and air figures here describe averages from named sources. They are not a promise for your day. For a swim or kayak stop on your dates, message us on WhatsApp +84 961 737 103.

Can you swim in Halong Bay in winter? The water in December to February

These are the figures from one sea-temperature site, based on the past 10 years, in degrees Celsius.

A different source, one climate model, works in Fahrenheit. It puts the cooler-water period from 23 December to 31 March, with February the coolest month at 67°F and August the warmest at 85°F. We keep the two sources apart because they use different units.

Our own guide gives May to September for warm water. Our small overnight boat page says the same, with October to April named for clear air. So the water is not the main reason to come in winter.

Air, mist and rain on the bay

Air is a different question from water. The nearest official station is Hai Phong, which is in the city and not on the bay. These are its 1991 to 2020 averages.

The climate model for Ha Long city puts its cool season from 10 December to 22 February, with January the coldest month, an average high of 68°F and a low of 57°F. The tourism board says January temperatures can be frigid.

Mist is part of the picture. Our weather guide describes December as cool, misty and cloudy, often foggy on the island. It also says October to December have the fewest rain days at Hai Phong. We keep the full month table in our lan ha bay weather month by month guide, so we do not repeat it here.

December, January or February: which month?

Ha Long Bay in December has the warmest water of the three on the sea-temperature site, 21.7°C. Our guide calls it cool, misty and cloudy. At Hai Phong, October to December have the fewest rain days.

Ha Long Bay in January is the coldest month in the climate model. Hai Phong's mean daily high is lowest of the three months, at 20.0°C. The tourism board's word for it is frigid.

Ha Long Bay in February has the coolest water of the three on the sea-temperature site, 19.1°C. Our guide calls it the driest month by rainfall, yet it has 13 rain days at Hai Phong. Dry on paper does not mean a clear sky.

Swimming and kayaking stops on a winter cruise

Here is what the ships list. Tulip includes kayaking and swimming in Lan Ha Bay. Celina of the Sea includes Bright Cave by bamboo boat or kayaking. Catherine includes a kayak or bamboo boat at Luon Cave.

None of our ship records says whether those stops run between December and February. We will not tell you they are on, and we will not tell you they are cancelled. We do not know, so ask us for your date and we confirm it before you pay.

• Celina of the Sea has a semi indoor pool that its own answers describe as for all seasons.
• Catherine has an outdoor pool on deck.
• Tulip has an outdoor jacuzzi on the sundeck.

Not everything on board depends on the water. Tulip lists a cooking class, sunset tea and sunrise tai chi. Celina lists a cooking class, a sunset party and sunrise tai chi, and its pool and mini golf run when the schedule allows. Catherine lists squid fishing, a cooking class, sunrise tai chi, a gym and mini golf. Tulip also lists cycling in Viet Hai village, squid fishing and karaoke.

Our overnight small boat lists optional kayaking and swimming. Our Lan Ha day trip keeps running in light rain, because the boat has covered deck space. That applies to the day trip only, not to the ships.

If you are still choosing a ship, our side-by-side look at the Ha Long Bay cruise ships helps, then send us your dates.

What a winter day on deck feels like

Writers disagree, and we think that is the honest picture. One cruise writer sailed in late November in cool air, low clouds, mist and periods of rain, and would not change it. The same writer adds that warmer months may suit swimming better.

Another writer, on a mid-February 2020 trip, says the rain, fog and cold really affected the time on the boat. That year the rain was somewhat unusual for the season, in that writer's words.

October to December is the commonly quoted clear window, and it is also the busiest. Nothing here promises calm or clear skies. If clear air matters most to you, ask us how the dates you have in mind look, and we answer from what we know.

If you still want the bay in winter

For our trips, October to April is quoted for clear air. The December to February stretch sits inside that range, but with the cool, misty days described above.

Our small overnight boat asks for a warm layer for the evening and is a simple boat at anchor. Tell us your dates first, and we confirm the stops, the boat and the price for those dates.

What to pack for a winter cruise

• Light layers that you can add or remove.
• A light jacket for the cooler months.
• A warm layer for the evening, which our overnight small-boat page asks for.
• A swimsuit for kayaking or beach stops.

For the rest of the list, see what to pack northern vietnam by season.

Storms, fog and whether boats sail

Our weather guide says storms come mostly from July to September. Four of our five ship notes warn about that period.

Boats do not sail in unsafe seas, and the captain decides. The harbour authority can also close the bay. The tourism board adds that tropical storms can sometimes cause cruise cancellations. On our own trips, if a trip cannot run, we tell you the evening before or first thing in the morning. You can move the date, switch to a land day or cancel.

Tulip adds a surcharge on 24 and 31 December. For what a cruise costs overall, see our guide to Ha Long Bay cruise prices, and we confirm the amount for your date.

What we read for this guide

We read our own ship and boat records, our bay weather guide, the official tourism board, WMO station averages, a climate model, a sea-temperature site and two cruise writers' accounts. Rules, fees and prices change quickly, so check close to your dates.