Ha Long Bay in December: cool, dry, and why reviews dip

December is a cool, dry month on Ha Long Bay, and a sound one for a cruise if you pack for cold evenings. Ten years of modelled weather give December days of 20.9°C, nights of 16.7°C and about four days with rain, and the sea averages 21.1°C, cold enough that a kayak is the likelier way onto the water. Its reviews sit below the yearly average, yet the two most recent Decembers came in almost level with their own years.

The review figures below come from the 645 guest reviews posted in December, out of 8,536 dated reviews we hold for 51 boats, counted on 9 October 2026. A review’s date is the day it went up, which can be weeks after the trip.

How cold is Ha Long Bay in December?

Mild in the afternoon, cold on deck after dark. The numbers are averages for December across 2016 to 2025 from ERA5 reanalysis, a model grid about 25 km wide that smooths extremes, so treat them as a typical December; they say nothing about your particular night.

December, 2016–2025	Average
Daytime high	20.9°C
Night-time low	16.7°C
Coldest night in the ten years	8.1°C
Rain in the month	19 mm (3 mm in the driest year, 68 mm in the wettest)
Days with 1 mm of rain or more	3.9
Sunshine	6.8 hours a day
Cloud cover	60%
Sea-surface temperature	21.1°C (four Decembers)

Guests mention the cold more often in December than across the year. Cold words turn up in 8 December reviews, 1.4% of those with text, against 0.6% across the year. One Athena Royal guest posting in early December 2023 found it too chilly to sit out on deck between stops and suggested indoor activities for the colder weeks. Another, posting at the end of December 2022 from La Regina Grand, said there was no hot water in the cold weather.

The catch is that cold lands on the very facilities you may be paying extra for. Another Athena Royal guest, posting on 28 December 2023, had looked forward to the big top-deck jacuzzi on a cold night and found it did not heat up. Our ship records cannot settle this for you: of the boats we track, exactly one record mentions a heated pool, and that on the operator’s word alone. For every other boat, nobody we have read publishes whether the water is warmed.

Can you swim or kayak in December?

Kayak, yes. Swim, only if you are hardy. A sea at 21.1°C is a long way below the 28.3 to 31.8°C of a summer sea, and the December reviews say so. A guest who took a three-day trip on Orchid Trendy at the end of December 2024 loved the kayaking and found the sea too cold to swim in.

Kayaking holds up well. It comes up in 9.6% of the 563 classified December reviews against 11.3% across the year, a little less often but far from rare. Our kayaking guide explains where each bay paddles.

Some boats give you warm water on board instead. A Stellar of the Seas guest posting on 26 December 2024 had good weather and used the pool, which the guest calls heated. A Mon Cheri guest posting on 14 December 2025 sat in the hot infinity pool in cold weather and counts it among the highlights. Neither boat’s records in our data say the pool is heated, so ask before you book.

Does it rain or get foggy in December?

Rain is rare. An average December brings 19 mm and fewer than four wet days in the ten-year record, which our weather by month sets beside the other eleven. Not one December review in our set uses a rain word, and none mentions fog.

Mist is the part we cannot measure. ERA5 does not model visibility, and nobody we can find publishes visibility records for the bay, so we cannot tell you how often the karsts sit in haze in December. Cloud covers 60% of the sky on an average December day and the sun shows for 6.8 hours, which suggests plenty of flat, grey light. That is our reading of the cloud figure, and the reviews neither confirm nor contradict it.

Storms are not a December problem on our wind record. One of the 50 gustiest days in ten years fell in December, on 28 December 2018 at 68.8 km/h, and the province’s rules for stopping boats in bad weather are set out in the weather guide.

Will it be crowded over Christmas and New Year?

Somewhat busier, by the guests’ own words, and more expensive. Crowd words appear in 4.6% of December text reviews against 3.0% for the year, and crowding as a subject in 7.5% of classified December reviews against 6.6%. The last eleven days of the month also carry the most reviews: 285 posted between the 21st and the 31st, against 157 in the first ten days and 203 in the middle ten, though a posting count is not a headcount.

What guests describe is the excursions. One Alisa Premier guest posting on 8 December 2025 found the outings a bit overcrowded and expected the same on any boat. Another on the same boat, posting on 30 December 2025, thought the visits could have been timed to dodge the worst of it. A Capella guest posting on New Year’s Eve 2024 praised the crew for reaching the popular sites before the big groups. Ask your seller what time the boat reaches the cave.

Expect a holiday surcharge on top of the fare. Of the 139 boats whose inclusions and exclusions we have extracted, 115 list a peak-season surcharge and 88 of those name Christmas. Renea’s terms pin it to 24 and 31 December. Only two lists carry an amount, $25 and $30 a person, and both date from December 2017. Nobody publishes this year’s figure, nor how full a given boat is on Christmas Eve, so ask for the total in dollars for your night before you pay.

Why are December reviews worse than average?

Mostly because of older Decembers. As posted, 44 of the 645 December reviews (6.8%) sit at one or two stars, against 426 of 8,536 (5.0%) across all months, which makes December the second-weakest month after September at 7.9%. The average rating is 4.62 against 4.69.

December posted in	Reviews	One or two stars	That whole year
2019	17	4 (23.5%)	5.8%
2022	36	6 (16.7%)	13.9%
2023	76	7 (9.2%)	8.1%
2024	208	11 (5.3%)	6.0%
2025	295	15 (5.1%)	5.1%

Four thinner Decembers (2017, 2018, 2020 and 2021) add 13 reviews and one low score.

December 2024 and December 2025 together hold 503 of the 645 reviews and 26 of the 44 low scores, 5.2%, against 5.3% for all twelve months of those two years. The remaining 142 reviews, from 2017 to 2023, carry 18 low scores between them, and 2022 was a poor year overall, with 13.9% of all its reviews at one or two stars.

The late-month figures are harder to read. Twenty-six of the 44 low scores went up between the 21st and the 31st, 9.1% of that stretch’s 285 reviews, against 5.7% in the first ten days and 4.4% in the middle ten. Posting dates cannot separate Christmas-week trips from earlier ones, so we cannot tell you whether the holiday itself drives it.

The subjects do shift. These rows count the 41 low December reviews with classified text against the 375 low reviews across the year. A subject counts once it is mentioned, praise or complaint alike.

Mentioned in a one or two star review	December	All year
The food	68.3%	54.4%
The cabin	51.2%	36.5%
Cleanliness	48.8%	33.6%
Getting there and back	24.4%	18.1%
Itinerary changed or cut	29.3%	29.3%

Reading the 44 low reviews themselves, six describe cockroaches or bed bugs on board, five of them in the cabin, spread over five boats and posted between 2019 and 2025. Four describe a booked cruise that was cancelled or moved before the trip began. One, posted on 16 December 2022, had the overnight part of the trip called off for weather. Forty-one classified reviews is a small base, and the cabin and cleanliness rows rest on about twenty reviews each. Cabins also come up more in December reviews generally, 37.7% against 30.6% for the year. Our guess, which the data cannot test, is that cold evenings keep people inside their cabins longer. Our guide to what guests complain about covers the year as a whole.

Which boats held up best in December?

Of the boats we publish, the three with the most December reviews each kept to two low scores or fewer. All four in the table pass our ranking rule of at least 100 reviews spread over twelve months or more.

Boat	Bay	December reviews	One or two stars	December average	All-year average	From, two sharing
Orchid Trendy	Lan Ha	87	1	4.93	4.93	$165 (read 8 Oct 2026)
Stellar of the Seas	Lan Ha	71	0	5.00	4.99	$366 (read 8 Oct 2026)
Alisa Premier	Ha Long	68	2	4.78	4.88	$155 (read 6 Aug 2026)
Renea	Bai Tu Long	16	0	4.81	4.78	$130 (read 6 Aug 2026)

Prices are per person for the cheapest cabin on a one-night trip, two sharing. Orchid Trendy’s single low score is a one-star review, posted 19 December 2024, whose text thanks the staff and calls the trip a great experience; we read it as a mis-tap, though we count it as posted. Stellar of the Seas went through 71 December reviews without a low score, and its pool is the one a December guest calls heated, but it costs more than twice as much as the other three. Alisa Premier anchors on the Ha Long side near Sung Sot Cave, and it is also the boat whose December guests describe crowded outings. Renea sails Bai Tu Long, on 16 December reviews, which is too few to say more than that it held up. The three bays compared will help you choose between them.

What should you ask before booking a December cruise?

Four questions, all by email so you have the answers in writing. First, is the pool or jacuzzi heated, and is there reliable hot water in the cabin? Second, what is the Christmas or New Year surcharge in dollars for your exact night, and is it already in the price you were quoted? Third, what time does the boat reach the main cave or beach, given that December guests name the excursions as the crowded part. Fourth, if the province stops boats sailing on your date, do you get a new date, a refund, or a partial one? Our cancellation policy guide shows how much the ordinary terms differ, and what is not included lists the other extras to check.

December cruise questions

Is December a good month for a Ha Long Bay cruise? Yes, if you are happy in a jumper on deck. Rain falls on fewer than four days in an average December, and only one of the 50 gustiest days in ten years fell in the month. Reviews posted in December 2024 and 2025 have one or two stars at 5.3% and 5.1%, close to their years’ 6.0% and 5.1%. The weak December figure in our month by month comparison is pulled up by the Decembers of 2017 to 2023, when 18 of 142 reviews were low.

What should I pack for December? Warm layers for the evening. Average December nights are 16.7°C, the coldest night in ten years reached 8.1°C, and on an open top deck after dinner it feels colder than that. A light waterproof is enough for rain at 19 mm in a typical month. Bring swimwear only if your boat confirms a heated pool or you are happy in a 21°C sea.

Should I book Christmas Eve or New Year’s Eve on board? Only after you have the surcharge in writing. Most boats’ published exclusions list one for Christmas (88 of 139), and none of the current lists we have read states the amount. Guests posting in the last days of December describe crowded excursions, and that stretch carries the month’s highest share of low scores, 9.1% of 285 reviews, though posting dates blur which trips those were.