Phuket sits on the Andaman Sea's exposed west coast, so its year splits cleanly into two: a long dry season most visitors plan around, and a wet, rough-sea monsoon that shuts down some of the reasons to come here at all. Get the season right and the choice of month barely matters. Get it wrong and you can end up with a beach you can't swim off and a boat trip that never leaves the pier.
This guide goes month by month, then covers the monsoon's real safety risk, the Similan Islands' closed season and the festival worth timing a trip around. For the rest of the island, see our Phuket travel guide.
Phuket weather by month
The table below uses long-term climate averages for Phuket. Treat it as a guide rather than a promise: any single year runs a bit hotter, cooler, wetter or drier.
| Month | Average high | Average low | Average rainfall |
|---|---|---|---|
| January | 32.7°C | 22.7°C | 35 mm |
| February | 33.9°C | 22.9°C | 40 mm |
| March | 34.3°C | 23.5°C | 75 mm |
| April | 34.0°C | 24.1°C | 125 mm |
| May | 32.8°C | 24.3°C | 295 mm |
| June | 32.3°C | 24.2°C | 265 mm |
| July | 31.9°C | 24.3°C | 215 mm |
| August | 31.6°C | 24.3°C | 245 mm |
| September | 31.4°C | 23.8°C | 325 mm |
| October | 31.5°C | 23.5°C | 315 mm |
| November | 32.0°C | 23.3°C | 195 mm |
| December | 31.9°C | 22.9°C | 80 mm |
Temperature barely moves through the year. Rainfall does the real work: January averages 35 mm and September 325 mm, and that gap decides when to visit.
The dry season: November to April
This is Phuket's high season, and for good reason. Rain is occasional rather than constant, the sea is at its calmest, and the west-coast beaches are safe to swim most days. December to March is the best stretch within that window, with the lowest rainfall and the clearest water. It's also the busiest and most expensive time on the island, especially over Christmas and New Year, so book flights, hostels and any boat trip well ahead.
The southwest monsoon: May to October
From about May to October, the southwest monsoon turns the Andaman Sea rough. Rain falls harder and more often, September and October are the wettest months, and the sea along Phuket's exposed west coast can turn dangerous to swim in.
Maya Bay on Koh Phi Phi also closes every August and September, and in 2026 it reopened on 1 October. Beyond the swimming risk, some boat trips and island resorts reduce their schedules or close for the season, and ferries to Krabi, Phi Phi and Koh Lanta run far less often. If your trip depends on a specific day trip or ferry crossing, the dry season is the safer bet.
When are the Similan Islands open?
The Similan Islands national park, one of the main reasons people base themselves in Phuket for a few days, closes completely for the monsoon, roughly mid-May to mid-October, because the crossing and the anchorages become too rough and unsafe. The 2026 closure ran from 16 May to 15 October. The park sets the exact dates each year, so check its announcement before you book. It reopens in mid-October and is at its best from December to April, when the crossing is calm and the water is clearest. Our Phuket travel guide has more on getting there, and our Thailand diving guide covers course and day-trip prices.
Festivals worth planning around
Phuket's Vegetarian Festival runs 10 to 18 October 2026, mostly around Old Town, with processions, pierced-cheek mediums and vegan "jay" food stalls. It falls right at the tail end of the wet season, so pack a rain jacket if you're going. Our Phuket Vegetarian Festival guide has the 2026 dates, the expected 2027 dates and how to watch respectfully.
The other date worth planning around is Christmas and New Year, the single busiest and most expensive fortnight of the dry season. Book well ahead if you want to be on the island for it.
Best time for...
- A first visit, beaches and boat trips: December to March, for the calmest sea and least rain.
- The Similan Islands: mid-October to April, while the park is open; December to April for the clearest water.
- A tighter budget: June to August, accepting rougher seas and less reliable ferries.
- The Vegetarian Festival: 10 to 18 October 2026, with a rain jacket packed.
- Avoiding the crowds and the highest prices: anything outside the last two weeks of December.
Phuket and our trips
None of our Thailand trips are based in Phuket itself, but two run through the same dry-season window this guide points to, on the Andaman coast nearby.
