When to cruise Ha Long Bay, from 8,316 guest reviews

Go in July if you want the best odds, and avoid September. That is the opposite of the advice you will read everywhere else, and it comes out of counting 8,316 guest reviews of the boats we track rather than repeating a climate table.

The usual advice — October to April, dodge the summer — describes the weather in northern Vietnam accurately enough. It just does not describe how trips turn out, and those are two different questions.

What guests said, month by month

Month	Reviews	Rated 1 or 2 stars	Average
January	727	4.1%	4.72
February	544	4.8%	4.66
March	795	5.9%	4.67
April	1,044	4.5%	4.72
May	766	5.2%	4.64
June	684	4.7%	4.72
July	878	2.8%	4.79
August	803	4.6%	4.73
September	336	9.8%	4.44
October	529	6.2%	4.61
November	566	4.2%	4.70
December	644	6.8%	4.62

Across all 8,316, one review in twenty sits at one or two stars. September runs at one in ten.

September is the month to skip

September carries nearly double the site-wide rate of bad reviews, the lowest average of any month, and the smallest volume of reviews in the year. The bad-review rate survives a check on years. Our reviews stop at 12 August 2026, so September has none from 2026, a mild year at 3.5%. On 2023 to 2025 alone September still runs at 10.0%, against 2.9% for July, 5.6% for August and 6.3% for October. The thin volume does not survive: on those years January, February and June each have fewer reviews.

Storms do turn up in two separate Septembers. In 2024 a guest describes being evacuated from a boat because of Typhoon Yagi, and praises the crew for how calmly it was handled. Another, three weeks later, describes a bay still a little battered. In 2025 a guest sailed just before a super typhoon and was back before the bay closed.

Seven reviews out of 336 mention a storm or typhoon, and they do not explain the low score. Four of the seven give five stars. Of September’s 33 one and two-star reviews, two mention a storm, both from one guest posting on two sister boats’ pages on 27 September 2025, whose cruise was cut short as the typhoon approached; that guest blames how the day was organised.

The years run the wrong way too. Of the three Septembers with more than 50 reviews, the worst, 2023, had none of the decade’s 50 windiest days, and five of its nine bad reviews came from three guests posting on one day. Yagi’s September in 2024 ran at 4 bad reviews out of 60. Our September guide has the breakdown. What drags the month down, we do not know.

September does bring real storms, and when the bay closes nobody sails. If your dates are fixed in September, book a boat with a written cancellation policy and read it before you pay. If your dates are movable, move them.

July scores best, and that surprised us

July is hot, humid, and firmly inside the season most guides tell you to avoid. It also has the lowest rate of one and two-star reviews of any month at 2.8%, and the highest average at 4.79.

We can offer two partial explanations and no proof. Heat is predictable in a way that storms are not, so almost nothing gets cancelled. And the things a July guest wants — swimming, the water slides, the kayaking — are exactly what the boats are set up to deliver, whereas a January guest is buying a view that fog may or may not provide.

Heat still costs you something. Guests writing in the hot months mention the sundeck being unusable in the middle of the day far more than they mention anything about the sea. If you are choosing between two boats in July, the one with a pool is not a luxury.

Winter: the view is the gamble

December and January carry fifteen mentions of cold weather between them, eight and seven, the most of any two neighbouring months in our set. A Vietnamese guest describes a cold snap of around ten degrees in the north and notes that the itinerary ran in full anyway, which matches what we see generally: winter cold does not cancel trips, it changes what the day feels like.

What it does change is the photograph. March draws the most remarks about fog and haze of any month, and guests split on it: some describe the mist as the best part, others booked a view and did not get one. Either way you are not owed a refund for weather that shows up.

The catch with winter is cabin comfort rather than the sea. A few guests report no hot water on cold mornings, and heating is not something any operator in our data publishes. If you are going between December and February, ask whether the cabin has heating and get the answer in writing.

August: watch how cancellations are handled, not whether they happen

August has the highest number of reviews mentioning a cancellation or a schedule change of any month. Reading them, the complaints are almost never about the weather itself. They are about what happened next: being driven several hours to a lounge before being told, or being moved onto a different boat.

We are not going to tell you which operators behave well here, because handling varies by month and we cannot verify what a company will do on your date. What we can tell you is that this is the question worth asking before you pay in the summer months, and that the one-star reviews of the specific boat you are considering are the fastest way to find out. Every product page here shows the full score distribution rather than the average alone, for exactly this reason.

What these numbers cannot tell you

The dates are posting dates, not travel dates. People write reviews days or weeks after getting home, so the month buckets lean late. A trip in the last days of August often lands in the September column. This blunts every finding here, and it is the main reason we present the months as a comparison rather than a forecast.

Weather is rare in reviews. Rain shows up in 0.3% of reviews, fog in 0.1%, storms in 0.2%. Most people describe the food, the cabin and the crew. The monthly differences above are real, but they emerge from scores, not from a pile of weather complaints.

We have not sailed in every month, and we hold no weather measurements of our own. Our Ha Long Bay weather page sets ten years of modelled data for one point in the bay beside these same reviews.

Common questions

So what is the single best month? July on our numbers, and January if you want a cooler day with almost as good a record. Both beat the October to November window that most guides recommend.

Is the rainy season really that bad? Not for scores. May to September are the wettest months on our weather page, and only September scores badly. Fewer than 30 of our 8,316 reviews mention rain at all.

What happens if a typhoon closes the bay? The authorities stop all sailings and the operator decides between a refund, a reschedule, or a night in a hotel. That decision is the operator’s policy, not a rule, which is why it belongs in writing before you pay.

Does the month change the price? Less than you would expect. The rates we track move with the boat, not the calendar. Choosing your bay and your stops will change your trip more than your month will.