Short answer
August is the heart of the Phuket monsoon: the Thai Meteorological Department's 1981–2010 normals give 286.8 mm of rain over 19.0 rainy days, and its forecast of 25 August 2026 expected waves of 2–3 metres in the upper Andaman Sea. Maya Bay is closed from 1 August to 30 September, the Similan Islands are closed until mid-October, and hotels are at their cheapest. Boat days still run when the sea allows, and Phang Nga Bay is the sheltered choice.
August: rain on about six days in ten
August is one of the two wettest months of the Phuket year. The Thai Meteorological Department's 1981–2010 normals for the Phuket station give 286.8 mm over 19.0 rainy days, with a mean daily maximum of 32.0 °C and a mean minimum of 25.3 °C. August and September together bring 648 mm, just under 30 percent of the year's 2,219.5 mm. The airport station in the north records 329.8 mm over 20.2 days, and the newer 1991–2020 table on Wikipedia's Phuket City page gives 308.7 mm and 16.9 days with 1 mm or more.
The Thai weather service's climate summary calls August and September the wettest period of the year across Thailand, with the west coast of the south peaking in September. Phuket 101 puts it simply: rain on about six days out of ten, usually only for part of the day. In the Royal Irrigation Department's figures, printed on Wikipedia's Phuket Province page, August has 79 percent humidity and 151.9 hours of sunshine.
The sea in August: 2 to 3 metres offshore, rougher on the west coast
The sea is at its roughest in the months around August. Phuket 101 rates it as rough with strong currents possible, says the rip tides can be treacherous, and notes that the water itself stays warm at 29 °C. For a sense of scale, the Thai Meteorological Department's forecast issued on 25 August 2026, reported by Asia News Network, expected waves of 2 to 3 metres in the upper Andaman Sea, above 3 metres in thunderstorms, and advised small boats there to stay ashore.
That was a forecast for a day, not for the month, and not for our route. It shows what a strong southwest monsoon day looks like, and why the operator, not the calendar, decides whether a trip sails. On our tours, if the sea is unsafe the operator moves the trip to another date or refunds it. Keep a spare day in your plans, and read the beach flags; our guide to rip currents and red flags explains them.
Maya Bay is closed in August
The national park closes Maya Bay every year from 1 August to 30 September. The Department of National Parks described its 2026 closure as running from 1 August to 30 September 2026, to let the reef and beach recover and to protect visitors during the southwest monsoon. On our Phi Phi and Maya Bay speedboat tour, which is from $75 per person, the bay is seen from the boat only during those dates.
The rest of the day stays on the route. Phuket 101 says Pileh Lagoon and Bamboo Island stay open as normal during the closure. The details we hold do not say whether the park fee of 400 baht per adult and 200 per child, which the operator collects in cash, changes while Maya Bay is closed, so ask us for your date. Our guide to Phi Phi in August and September covers the closure dates and what the day looks like.
Phang Nga Bay: the day that suits August
If you want a boat day in August without the open sea, Phang Nga Bay is the better fit. Phuket 101 says the bay is protected from monsoon swell by its limestone cliffs, that the scenery is more dramatic under heavy skies, and that the sea there is always calm, so motion-sickness medicine is not needed. We would not promise that it is always calm, but the shelter is real. Our James Bond Island and Phang Nga Bay canoe tour is from $85 per person and the details we hold for it list no closed season.
The day runs about 8.5 hours from Laem Nga pier on Koh Siray, with hotel pickup between about 7:00 and 8:00 am and a return at about 5:00 pm. It includes the national park fee, lunch at Koh Panyee, sea canoeing at Hong Island with a professional paddler and snorkelling gear. Low tide can change the order of the stops or shorten the canoe route into the lagoon, and the guide times James Bond Island around the tide and the crowds. Our Phi Phi or James Bond Island comparison puts the two days side by side.
What the monsoon leaves on the beaches
The monsoon brings rubbish ashore. Ao Phang Nga National Park's head said in a September 2026 report that every monsoon season, currents and waves carry marine waste from outside the area onto islands and beaches. The park organised a clean-up of monsoon rubbish around its ranger station on Koh Lawa Yai on 19 September 2026, with more than 40 volunteers and a plan for continuing beach monitoring through the monsoon.
Phuket 101 makes the same point for Phuket: small, remote beaches can look neglected in the low season because of the rubbish the sea brings in, so the five main beaches are better bets then. For a visitor, the practical advice is modest. Do not expect postcard sand everywhere, choose the busier beaches over the remote ones, and do not drop litter, which is also what Thailand's environment minister asked of visitors when the Andaman season opened in October 2026.
Prices, crowds and local festivals in August
August is the cheapest month on the island, says Phuket 101. Luxury resorts that charge premium rates in December become affordable, many hotels offer free upgrades, breakfast deals and spa credits, and the island is more peaceful, with fewer traffic jams and restaurants that do not need reservations. Booking a spa treatment early on a wet day is its advice, because everyone in the hotel has the same idea. Tour prices do not drop in the same way, so the saving is mostly in the room.
Two dates fall in August. Wikipedia's list of Thai public holidays gives 12 August as the Queen Mother's Birthday, which is also National Mother's Day. The Por Tor festival, the Hungry Ghost Festival of Phuket's Hokkien Chinese community, follows the lunar calendar; Phuket 101 says that in 2026 it ran from 19 August to 6 September, with the main ceremony on 27 August and red turtle-shaped ang ku cakes as the symbol, so the dates move each year.
Who August suits, and what to pack
August suits budget travellers, anyone who likes a quiet island and dramatic skies, and visitors who treat rain as part of the trip. That makes the sheltered Phang Nga Bay day the better fit than the open-sea days. It does not suit anyone who needs a calm west-coast beach, a Similan trip or Maya Bay itself, or who cannot tolerate a changed plan. The speedboats do not take pregnant women, infants under 1 year or guests over 70.
Pack a light raincoat or compact umbrella, waterproof sandals, a waterproof bag for phone and camera, sunscreen and seasickness tablets, as Phuket 101 advises, and swimwear and a towel for the boat; towels are not included, and a dry bag keeps the phone safe. For the months around it, read Phuket in July and Phuket in September.
Practical checklist
- Do not plan on landing at Maya Bay: it is closed from 1 August to 30 September.
- Hold a spare day for any boat trip, since the operator moves or refunds trips when the sea is unsafe.
- Treat red flags as a ban on swimming; use a pool or an east-coast beach.
- Pack a rain layer, a dry bag, seasickness tablets and a change of clothes.
- Ask us on WhatsApp whether the Phi Phi park fee applies on your date.
Questions and answers
Is August a bad month to visit Phuket?
It is a low-season month: the Thai normals give 286.8 mm of rain over 19.0 rainy days and the west-coast sea is rough. In return, hotels are at their cheapest and the island is quiet, and many tours still run.
Is Maya Bay open in August?
No. The national park closes it every year from 1 August to 30 September, and the Department of National Parks gave the same dates for 2026. On our Phi Phi tour you see the bay from the boat only.
Does the James Bond Island tour run in August?
Yes. The details we hold list no closed season, and Phuket 101 says the limestone cliffs shelter Phang Nga Bay from the monsoon swell. If the sea is unsafe, the operator moves the trip or refunds it.
How rough is the sea in Phuket in August?
Rough on the west coast, according to Phuket 101, which warns of strong currents. A forecast on 25 August 2026 expected waves of 2 to 3 metres in the upper Andaman Sea. East-coast beaches and Phang Nga Bay are calmer.
Are the Similan Islands open in August?
No. Phuket 101 says they close from mid-May to mid-October, and our Similan tour runs only from 15 October to 14 May.