Phuket is driest from December to March and wettest from May to October, when the southwest monsoon brings 260–400 mm of rain a month to the airport station and big waves to the west-coast beaches. It is hot all year: daytime highs stay between 31 and 34 °C, and nights rarely fall much below 23 °C.
The figures on this page are the Thai Meteorological Department's (TMD) official averages for 1991–2020. Phuket has two weather stations in that table, and they differ: the airport in the north of the island records 2,664 mm of rain a year, Phuket Town 2,272 mm. We use the airport station, which is closer to the northern beaches, and give the town figure where it helps. Averages describe a typical year, not the coming one.
Phuket climate at a glance (TMD, Phuket Airport station, 1991–2020)
- Driest month
- February: 32.0 mm, 4.3 rainy days
- Wettest month
- September: 399.2 mm; most rainy days in October (23.1)
- Hottest days
- March: average high 33.6 °C
- Coolest nights
- December to February: average low 22.9–23.1 °C
- Rain per year
- 2,664.3 mm at the airport; 2,271.5 mm in Phuket Town
- Wind
- From the east November–March, from the west May–October
- Similan Islands
- Open 15 October–15 May only
Phuket's twelve months in figures
The table shows the average daily high and low, the monthly rainfall and the number of days with any measurable rain (0.1 mm or more) at Phuket Airport.
| Month | High / low °C | Rain (mm) | Rainy days |
|---|---|---|---|
| Jan | 32.1 / 22.9 | 66.2 | 6.8 |
| Feb | 33.2 / 23.1 | 32.0 | 4.3 |
| Mar | 33.6 / 23.7 | 117.2 | 8.5 |
| Apr | 33.5 / 24.2 | 143.7 | 12.9 |
| May | 32.4 / 24.6 | 277.5 | 19.8 |
| Jun | 31.8 / 24.6 | 314.0 | 18.7 |
| Jul | 31.5 / 24.6 | 260.4 | 19.4 |
| Aug | 31.3 / 24.7 | 378.2 | 19.8 |
| Sep | 30.9 / 24.1 | 399.2 | 21.9 |
| Oct | 31.0 / 23.7 | 370.5 | 23.1 |
| Nov | 31.4 / 23.5 | 219.0 | 17.5 |
| Dec | 31.3 / 23.1 | 86.4 | 10.7 |
Two things stand out. The temperature hardly changes: the gap between the warmest and coolest month is under three degrees by day. And the rain does not arrive gradually: it doubles from April to May. Humidity follows the rain, from an average of 74 % in February to 85 % in October. For the country as a whole, our Thailand weather by month guide puts Phuket next to Bangkok, Chiang Mai and the Gulf.
December to March: the dry season
From December to March the wind blows from the east, across the island and out to sea, so the west-coast bays are usually calm and clear. The airport averages 117 mm or less and no more than 8.5 rainy days in each of these months, and February is the driest of the year with 32 mm. Phuket Town is drier still in February, at 24 mm.
This is the high season for a reason, and it is when beach holidays, island boat trips and diving work best. Days are hot rather than mild, with highs of 32–34 °C, and the strongest sun of the year comes in March, the hottest month. Our page on heat and sun safety applies on any beach day.
April: the hot, stormy changeover
April is a month of transition. The wind starts to swing to the west and northwest, and the TMD table records more thunderstorm days in April (6.4 on average) than in any other month at the airport. Rain rises to 144 mm, still less than half of what the monsoon months bring, and the sea is usually still swimmable on the main beaches.
May to October: the southwest monsoon
From May the southwest monsoon sets in over the Andaman Sea. In 2025 the TMD dated the start of the rainy season to 15 May. From then until October the wind blows from the west, straight onto Phuket's main beaches, and every month averages 260–400 mm of rain and about 19–23 rainy days at the airport. September is the wettest month (399.2 mm) and October has the most rainy days (23.1).
A common belief is that only September and October are really wet. The figures do not support that: May, June and August each bring 277–378 mm at the airport, more than double any dry-season month. The highest one-day total recorded at the airport in the period was 211.9 mm, in August.
The island is green and quieter in these months, and many travelers enjoy them. Plan for rain: indoor or town days in Old Phuket Town, flexible boat plans and a hotel with a pool. Our guide to the rainy season in Thailand covers travel in these months more generally.
Monsoon waves and red flags on the west coast
The real risk in the low season is not the rain but the sea. With the wind onshore, the west-facing beaches from Mai Khao to Nai Harn get heavy surf and rip currents, and lifeguards raise red flags when swimming is unsafe. In May 2026 lifeguards put up red flags at Nai Thon beach, which is known for rip currents, because of monsoon conditions, strong winds and storms. A red flag means no swimming, however calm the water near the shore looks.
Our guide to rip currents and beach flags explains how to spot a rip and what to do if one takes you out. Swim only at beaches with lifeguards in these months, and stay out of the water on red-flag days.
A flat sea at breakfast is no promise for the afternoon. In the monsoon months the waves on Phuket's west coast can build within hours as squalls come in from the Andaman Sea. Check the flag each time you go down to the water, not just once in the morning.
Which beaches are calmer in the low season
Phuket's east coast faces Phang Nga Bay and is sheltered from the southwest wind, so the water there is calmer from May to October. It is mostly mangrove, piers and small coves rather than long sandy beaches, so it suits a swim on a rough day more than a beach holiday. On the west coast, conditions vary from bay to bay and day to day; our comparison of Phuket's beaches goes through them one by one, including the beaches where surf schools work in the monsoon.
Boat trips into the sheltered bay are often still possible in the wet months, when the open-sea routes are rough; our guide to Phang Nga Bay and James Bond Island covers the day trips. Ferries and speedboats can be cancelled at short notice in any monsoon month.
The Similan closure and storm warnings
The Similan Islands, the best-known dive and snorkel trip from Phuket and Khao Lak, are open only from 15 October to 15 May each year and close for the whole southwest monsoon. Our page on the Similan Islands explains the e-ticket system and the daily visitor cap.
Storms can hit outside the averages. In late October 2026 the Tourist Police reported helping people during flooding and landslides in Patong. The TMD issues advisories in English, and our guide to weather warnings and storms shows where to find them and how phone alerts work.
November: the step down
November is the month when Phuket changes back. Rain falls to 219 mm at the airport, with 17.5 rainy days, and the TMD table gives the east as the prevailing wind again. It is still a wet month by most standards, so keep a spare day for boat trips. December, with 86 mm and 10.7 rainy days, is the start of the dry season proper.
Phuket, Krabi or the Gulf: choosing by month
Krabi, across Phang Nga Bay, has the same seasons on a smaller scale. Its TMD station records 2,180.7 mm a year, less than Phuket Airport, and its wettest month is October (292.9 mm). Our comparison of Phuket or Krabi weighs the two on beaches, flights and atmosphere rather than weather.
If you have to travel between June and August and want a dry beach, the Gulf side is the answer: Koh Samui averages only 102–134 mm a month then. In November the opposite is true, as Samui has its wettest month. Our page on the best time for the Thai islands compares the Andaman, Gulf and eastern islands, and the best-time-to-visit tool lets you pick a month and see which regions suit it. Our Phuket guide covers the island itself.
Frequently asked questions
What is the best month to visit Phuket?
For calm seas and the least rain, February is the best month: the airport station averages 32 mm and 4.3 rainy days. December to March as a whole is the dry season. January and February are also slightly less hot than March and April.
Is it worth going to Phuket in the rainy season?
Yes, if you accept rough seas and some wet days. The island is greener and quieter, but the west-coast beaches often fly red flags from May to October, the Similan Islands are closed and boat trips may be cancelled. Plan town days and flexible excursions.
What is the wettest month in Phuket?
September, with 399.2 mm on average at Phuket Airport (350.4 mm in Phuket Town), according to TMD's 1991–2020 averages. October has the most rainy days, 23.1 at the airport, and is almost as wet.
Is Phuket in May too rainy?
May is the first month of the southwest monsoon. The airport averages 277.5 mm and nearly 20 rainy days, so expect regular showers and rougher seas, especially in the second half of the month. The Similan Islands close on 15 May.
When is Phuket coolest?
Phuket is never really cool. The coolest nights come from December to February, with average lows of about 23 °C at the airport. The lowest temperature recorded there in 1991–2020 was 17.9 °C, in February.
Sources
- Thai Meteorological Department – Climatological data 1991–2020 (Phuket Airport, Phuket, Krabi and Ko Samui stations) (checked November 2026)
- Thai Meteorological Department – Monthly climate summary, May 2025 (checked October 2026)
- Tourist Police Bureau – Assistance during flooding in Patong (26 October 2026) (checked October 2026)
- Bangkok Post – Man swept out to sea amid strong winds in Phuket (May 2026) (checked October 2026)
- Department of National Parks – Similan Islands open 15 October to 15 May (7 August 2026, Thai) (checked November 2026)