Short answer
December is the first month of the Phuket peak season: the Thai Meteorological Department's 1981–2010 normals give 72.4 mm of rain over 9.3 rainy days, far less than November's 177.4 mm, with the coolest nights of the year at 24.4 °C on average. Phuket 101 rates the sea as calm and clear, with no red flags. Maya Bay and the Similan Islands are open and every boat day runs, but hotel rates switch to high-season levels, so book rooms early and boat days a few days ahead.
December: the dry season settles in
December is the first fully dry-season month. The Thai Meteorological Department's 1981–2010 normals for the Phuket station give 72.4 mm over 9.3 rainy days, against 177.4 mm and 15.4 days in November. It is still wetter than January (30.3 mm) and February (23.9 mm), so a shower is not a shock. The mean daily maximum is 31.7 °C and the mean minimum 24.4 °C, the coolest nights of the year, and the station's lowest recorded temperature in the table is 18.4 °C, in December.
The airport station in the north records 67.4 mm over 10.0 days, and the newer 1991–2020 table on Wikipedia's Phuket City page gives 82.0 mm and 7.8 days with 1 mm or more. The Royal Irrigation Department's figures on Wikipedia's Phuket Province page give humidity of 75 percent and 198.4 hours of sunshine, about 6.4 hours a day. Phuket 101 puts the UV index at 10, which it labels very high, the lowest reading in its monthly guides.
The sea in December: calm, clear, no red flags
December is the month the sea settles. Phuket 101 rates it as calm and clear, with a water temperature of about 28 °C, says all beaches are safe for swimming and the sea is at its most photogenic with good visibility for diving and snorkelling. It describes the beaches as superb with no red flags. The Thai Meteorological Department's climate summary puts the northeast monsoon from mid-October to mid-February, with winds over southern Thailand mostly from the east or northeast.
Bangkok Airways' February 2026 guide gives November to April as the peak season on Phi Phi, with calm seas and great visibility. Wikivoyage says the waves at Ya Nui beach are gentle from December to March. None of this removes the risk of a windy day, and a speedboat can be bumpy in open water, but on our tours the operator moves the trip to another date or refunds it if the sea is unsafe. Our Phuket in January guide covers the same calm in the month after.
Boat days in December
Every classic boat day runs. The national park closes Maya Bay only from 1 August to 30 September, so December is a landing month. Phuket 101 calls December the perfect month for island trips, from Phi Phi and the Similans to lesser-known ones such as Rang Yai and Maiton, with excellent visibility for snorkelling and diving. Our Phi Phi and Maya Bay speedboat tour costs from $75 per person, takes about 8.5 hours and starts with hotel pickup between about 7:00 and 8:30 am; the speedboat leaves Royal Phuket Marina at about 9:30.
For the Similans, our speedboat day costs from $105 per person, runs between 15 October and 14 May and takes 12–13 hours door to door. At Maya Bay the park lets in rounds of up to 375 people an hour between 07:00 and 18:00, according to its December 2021 announcement, and swimming is not allowed. Our Phi Phi or James Bond Island comparison helps you choose between the Phi Phi day and Phang Nga Bay.
Peak-season prices and how far ahead to book
December is when prices change. Phuket 101 says hotel rates switch to high-season levels, especially over Christmas and New Year, and its high-season guide puts the peak at mid-December to February, when prices run 30–50% above the low season. Beachfront hotels sell out weeks ahead, particularly over New Year. It advises booking at least one to two months ahead for December and January, and says tuk-tuk drivers and night-market vendors are less willing to negotiate.
Boat days fill too. Phuket 101 says the popular tour boats fill up days in advance in the peak season, so send us your date and hotel on WhatsApp early if your dates are around Christmas and New Year; we confirm availability, the pickup time and the total before you pay. Phuket 101 puts the peak at mid-December and calls November to early December the transition, when prices are climbing but not yet at their peak, so early December is the cheaper part of the month.
Dates that matter in December
Wikipedia's list of Thai public holidays gives 5 December as King Bhumibol Adulyadej's Birthday, also observed as National Day and Father's Day, and 10 December as Constitution Day, both fixed dates. Wikipedia's Phuket page and Wikivoyage both place the Phuket King's Cup Regatta, a yachting event hosted at Kata Beach Resort, in December. Check the exact days for your year, because event dates are set annually.
Christmas and New Year bring their own rhythm. Phuket 101 says hotels host Christmas evening events with buffets by the pool and fireworks, and that New Year's Eve is a night of parties, with beach clubs and Bangla Walking Street open until morning. It also warns that some big hotels make a New Year dinner compulsory and can charge a lot for it, so check before you book. In Patong, the whole beach fills with people watching fireworks and releasing lanterns.
Cool nights, bright days and what to pack
December feels cooler than it is. Phuket 101 says temperatures under 25 °C are 'cold' for locals, and that December and January can feel surprisingly cool at night, so it suggests a light layer if you ride a motorbike in the evening. Days are bright, and the UV index of 10 means sunscreen is still essential. For a boat day, bring swimwear, a towel (towels are not included), a hat, a dry bag for the phone and sunscreen without oxybenzone, octinoxate, 4-MBC or butylparaben.
The park fee on our Phi Phi tour is 400 baht per adult and 200 per child, collected in cash by the operator; we give this as what the operator collects, not as an official rate. Our tour schedule lists the packing in full, and the speedboat is not suitable for pregnant women, infants under 1 year or guests over 70.
Who December suits, and who might choose November
December suits first-time visitors, snorkellers, couples and families who want a calm sea and are ready to book ahead. Phuket 101 calls December and January the perfect months to enjoy the island's beauty and take superb photographs. It also suits anyone who wants a festive week by the sea and does not mind that the festive week comes with festive prices.
It does not suit travellers on a tight budget or those who dislike crowds, and it is the wrong month for a last-minute plan. For lower prices and still-good weather, Phuket 101 points to November or March. For quieter beaches in December itself, it suggests Nai Harn, Surin and the northern beaches. If you are comparing the Andaman and Gulf coasts for the same dates, read our Andaman or Gulf coast guide.
Practical checklist
- Book beachfront hotels one to two months ahead, and earlier for Christmas and New Year.
- Check whether your hotel makes a New Year dinner compulsory before you book.
- Send us your boat-day date and hotel a few days ahead, or earlier around Christmas.
- Pack sunscreen without the four banned chemicals, a hat, a dry bag and a light evening layer.
- Keep cash for the Phi Phi park fee: 400 baht per adult and 200 per child on our tour.
Questions and answers
Is December a good month to visit Phuket?
Yes, for most travellers. The Thai normals give 72.4 mm of rain over 9.3 rainy days, and Phuket 101 rates the sea as calm and clear. The trade-off is peak-season prices, especially around Christmas and New Year.
Does it rain in Phuket in December?
Occasionally. December has 72.4 mm over 9.3 rainy days in the Thai normals for the Phuket station, more than January or February but far less than November.
Is the sea calm in December?
Usually. Phuket 101 says it is calm and clear with no red flags, at about 28 °C. A speedboat can still be bumpy in open water, and on our tour the operator moves the trip or refunds it if the sea is unsafe.
How far ahead should I book in December?
Phuket 101 advises one to two months for beachfront hotels in December and January. Popular tour boats fill up days ahead, so send us your boat date and hotel early.
Are Maya Bay and the Similans open in December?
Yes. The national park closes Maya Bay only from 1 August to 30 September, and our Similan tour runs from 15 October to 14 May.