Phuket's weather in December is the best of the year for boat days. The northeast monsoon is fully in place, so the Andaman Sea on Phuket's west side is usually flat in the mornings, with clear water and long sunny spells. Expect daytime highs around 31–32°C, nights around 24°C, and a sea of about 28°C. Rain averages only around 60–80 mm for the whole month, mostly in short, rare showers. Every Simba Sea Trips tour is running in December 2026, including the Phi Phi Sunset & Shark tour.
In December the weather rarely decides your trip. Crowds and availability do. December is Phuket's peak month, and the run from Christmas to New Year is the busiest stretch of the year at sea and on land. The calm mornings are also when the big day-tripper fleets head out, so an early start and a smaller boat make the most difference to your day.
Simba Sea Trips has run small-group boat tours out of Boat Lagoon Marina since 2005, with a maximum of 18 adults on board. After twenty Decembers on this water, we know the forecast is almost always good. What changes a December day is timing, and whether you reach the famous spots before everyone else does.
Below you'll find the weather numbers, how the sea behaves week by week, which tours run and why, the new direct flights, and what to pack. If you're still choosing a month, start with our month-by-month guide to the best time to visit Phuket.
Phuket weather in December at a glance
| What | Typical December | What it means on a boat |
|---|---|---|
| Air temperature | About 24°C at night, 31–32°C by day | Strong sun by mid-morning, so cover up and bring sunscreen |
| Sea temperature | About 28°C | Warm enough to snorkel as long as you like, no wetsuit needed |
| Rainfall | Roughly 60–80 mm for the month, on only a handful of days | A passing shower at most, rarely enough to change plans |
| Wind | Steady from the northeast | Phuket's west side and the Phi Phi crossing are on the sheltered side |
| Sunrise / sunset | Around 6:40am / 6:15pm | Sunrise at sea on early departures, golden light on the way home |
These are long-run averages from published climate data, not a forecast. Any single day can be the exception.
Why December is so settled
From May to October the southwest monsoon pushes wind and swell from the Indian Ocean onto Phuket's west coast. The wind swings round in November, and by December the northeast monsoon is fully in place. Dry air comes down over the mainland, and Phuket's west coast, Phi Phi and the open water in between are sheltered from it. That's why December mornings are often glassy, and why underwater visibility is usually at its best.
December weather isn't perfect every day, though. A brisk northeasterly can put a light chop on the water by afternoon, and sometimes a late shower drifts over the island. We still check the marine forecast every morning before we set out.
December week by week on the water
| When | Sea, sky and crowds | Good to know |
|---|---|---|
| Week 1 (1–7 Dec) | Dry and calm, with lighter crowds than later in the month | The Phuket King's Cup Regatta usually starts in early December. 5 December is a national holiday (Father's Day) |
| Weeks 2–3 (8–19 Dec) | Settled high season. Flat mornings, clear water | Often the best balance of weather and availability. 10 December (Constitution Day) is a national holiday |
| Week 4+ (20–31 Dec) | Peak season. Same great conditions, the busiest week of the year | Book tours well ahead for Christmas and New Year's Eve. Early departures matter most now |
This is the usual pattern, not a promise. A late-season disturbance can bring a wet day or two, though it's uncommon in December.
Which Simba tours run in December, and why
- Phi Phi Sunrise tour: our best answer to December crowds. We leave Boat Lagoon early, so you watch the sunrise at sea on the way out, about 1 hour 10 minutes by speedboat, and reach Maya Bay before the day-tripper fleet.
- Phang Nga Bay & James Bond Island: sheltered water among the limestone karsts, and the smoothest ride on the rare breezy day. It suits families and anyone prone to seasickness.
- Phi Phi Sunset & Shark tour: runs in the dry season, November to April, and December is one of its most reliable months. We pause it from May to October because afternoon thunderstorms are much more likely, and it's an evening open-water crossing.
- Private charters: your own boat for your group, at a set price per boat rather than per person. Popular with families and groups over the festive weeks. Options include the Phi Phi sunrise private charter, the Krabi private charter to Ko Hong and Railay, and Coral Delight in southern Phuket. See all private charters, or read when to book a charter.
Prices are live on each tour page and all-inclusive, with national park fees already covered.
What about the Similan Islands?
The Similan and Surin national parks are open for the 2026–27 season (dates, hours and fees here), and December is one of their best months. We don't run Similan day trips from Phuket. It's a long open-water run, and we'd rather not put guests through it at speed in a single day. Our Similan Islands page explains why and covers how to go another way.
Getting here in December 2026
This is the first December with three new long-haul routes into Phuket. Virgin Atlantic started flying direct from London Heathrow on 18 October 2026, and Edelweiss flies nonstop from Zurich over the winter season. Kuwait Airways began a twice-weekly direct service from Kuwait City on 27 October 2026. Flights over Christmas and New Year fill early, so book flights and tours together if your dates are fixed.
What to pack for a December boat day
Pack for strong sun rather than rain. Bring a thin long-sleeved top, reef-safe sunscreen, sunglasses, a hat that won't blow off, and a small dry bag for your phone. A light layer helps on an early-morning sunrise departure, when the breeze at speed can feel cool. We provide snorkel gear, life jackets and floating aids.
Planning Phuket in December
Want the quietest version of a famous spot? Take the Phi Phi Sunrise tour. Travelling with family or prone to seasickness? Choose Phang Nga Bay. Visiting over Christmas or New Year? Book as soon as your dates are set, because the festive week sells out first. Arriving in late November? See our guide to Phuket weather in November. For the rest of the year, see what runs month by month, or browse our join-in tours. Every trip leaves from Soho Pool Club at Boat Lagoon Marina.
Updated November 2026 for the 2026–27 dry season.
