# Thailand's climate and seasons, coast by coast Source: https://www.thailandpropertyinvestor.com/living/climate-and-seasons Updated: 2026-11-14 Publisher: Thailand Property Investor (Omnia Capital Group) ## The short answer Thailand's two coasts have opposite wet seasons. The Andaman coast, including Phuket and Krabi, is dry from December to March and wet from May to October. Koh Samui, on the southern Gulf, is at its wettest from October to December and dry from February to April. Hua Hin and Pattaya, on the upper Gulf, are drier all year with a short peak in September and October. The north is cool and dry from November to January, then smoky from February to April. ## Key points - The south-west monsoon runs from mid-May to mid-October and soaks the Andaman coast, with Phuket's rainfall peaking at about 361 mm in September. - Koh Samui's rain arrives later, with about 445 mm in November, and its driest stretch runs from February to April. - Hua Hin is the driest of the resort areas at about 936 mm a year, less than half of Phuket's 2,220 mm. - Chiang Mai is cool and dry from November to January, and its air is unhealthy during the burning season from February to April. - A home on the Andaman coast and a home on Koh Samui have complementary seasons, which matters for both use and rental income. Thailand's two coasts have opposite seasons, and that should shape where you buy. The Andaman coast is dry from December to March and wet from May to October. Koh Samui, on the southern Gulf, takes its heavy rain from October to December and is dry from February to April. The upper Gulf towns of Hua Hin and Pattaya are drier than either all year. The north is cool in winter and smoky in spring. ## The three seasons and two monsoons Thailand's year has three seasons: - **Hot season**, mid-February to mid-May. - **Rainy season**, mid-May to mid-October, driven by the south-west monsoon from the Indian Ocean. August and September are the wettest months for most of the country. - **Cool season**, mid-October to mid-February, driven by the north-east monsoon, which brings cooler, dry air to most of Thailand. The southern peninsula, where most resort property is, behaves differently. The south-west monsoon hits the west-facing Andaman coast directly. The north-east monsoon brings heavy rain to the east-facing Gulf coast around Koh Samui, peaking from November to January. ## Rainfall month by month Average monthly rainfall in millimetres. | Month | Phuket | Krabi | Koh Samui | Hua Hin | Pattaya | Chiang Mai | | --- | --- | --- | --- | --- | --- | --- | | January | 30 | 32 | 127 | 25 | 16 | 11 | | February | 24 | 43 | 64 | 14 | 20 | 10 | | March | 74 | 98 | 116 | 51 | 47 | 20 | | April | 143 | 147 | 83 | 47 | 68 | 54 | | May | 260 | 172 | 132 | 96 | 121 | 168 | | June | 213 | 193 | 134 | 82 | 132 | 118 | | July | 258 | 201 | 117 | 90 | 104 | 149 | | August | 287 | 266 | 102 | 67 | 91 | 223 | | September | 361 | 275 | 118 | 130 | 214 | 207 | | October | 320 | 324 | 295 | 250 | 225 | 124 | | November | 177 | 180 | 445 | 73 | 57 | 41 | | December | 72 | 68 | 263 | 12 | 12 | 14 | | Year | 2,220 | 1,999 | 1,994 | 936 | 1,106 | 1,139 | Phuket figures are for Phuket Town. The airport station, in the north of the island, is wetter at about 2,475 mm a year. ## The Andaman coast: Phuket and Krabi The dry season runs from December to March. This is when [Phuket](https://www.thailandpropertyinvestor.com/areas/phuket) and [Krabi](https://www.thailandpropertyinvestor.com/areas/krabi) earn most of their rental income, and when owners from Europe want to be in residence. From May the south-west monsoon arrives. Phuket Town averages 18 to 23 rainy days a month from May to October, and September and October each bring more than 300 mm. The practical issue is the sea as much as the rain. West-coast beaches such as [Bang Tao](https://www.thailandpropertyinvestor.com/areas/phuket/bang-tao), [Surin](https://www.thailandpropertyinvestor.com/areas/phuket/surin) and [Kamala](https://www.thailandpropertyinvestor.com/areas/phuket/kamala) face the open Andaman, and swimming is often unsafe in these months. [Cape Yamu](https://www.thailandpropertyinvestor.com/areas/phuket/cape-yamu), on the east coast, faces sheltered water. Krabi follows the same pattern with its peak in October. Passenger boats are at greater risk in rough monsoon seas, so check conditions before island crossings. ## The Gulf: Koh Samui, Hua Hin and Pattaya The Gulf has two climates, not one. **Koh Samui** sits in the southern Gulf and catches the north-east monsoon. October, November and December together bring about 1,000 mm, half the year's total, with November the peak at about 445 mm. January can still be wet. February to April is the driest stretch, and the middle of the year stays moderate at 100 to 135 mm a month while Phuket is soaked. That makes [Koh Samui](https://www.thailandpropertyinvestor.com/areas/koh-samui) the natural complement to an Andaman home, and supports a second letting season in July and August. **Hua Hin and Pattaya**, on the upper Gulf, are drier throughout. [Hua Hin](https://www.thailandpropertyinvestor.com/areas/hua-hin) averages just 936 mm a year. Only October exceeds 200 mm, and December to February are almost rainless. [Pattaya](https://www.thailandpropertyinvestor.com/areas/pattaya) is similar at 1,106 mm, with September and October the wet months. For dependable weather across twelve months, these are the driest of the resort areas. ## The north: Chiang Mai [Chiang Mai](https://www.thailandpropertyinvestor.com/areas/chiang-mai) has a true cool season. From November to January, average lows are 16 to 20°C and highs about 30°C, with almost no rain. It then heats quickly: April averages a daily high of 36.7°C. Rain falls from May to October, peaking in August at about 223 mm. The drawback is the burning season. From roughly February to April, smoke from crop burning, forest fires and land clearing across northern Thailand and neighbouring countries collects in the mountain valleys. On 16 April 2026 Chiang Mai's air quality index passed 150, in the unhealthy range, and the city was among the ten most polluted major cities in the world. Relief comes only with consistent rain. [Bangkok](https://www.thailandpropertyinvestor.com/areas/bangkok) also has high air pollution at times. ## Driest and wettest months by area | Area | Driest months | Wettest months | | --- | --- | --- | | Phuket and Krabi | December to March | September and October | | Koh Samui | February to April | October to December | | Hua Hin and Pattaya | December to February | September and October | | Chiang Mai | November to February, with smoke from February to April | August and September | ## What this means for buyers **For your own use.** Match the dry season to the months you can be there. A family tied to European summer holidays will find Phuket at its wettest in July and August, and Koh Samui or Hua Hin a better fit. **For rental income.** Occupancy and nightly rates follow the weather, so an Andaman property earns most of its income in the dry months. Ask any developer or manager for monthly, not annual, occupancy figures. See [rental yields in Thailand](https://www.thailandpropertyinvestor.com/guides/rental-yields-in-thailand). **For the building.** Humidity and salt air are hard on finishes, air conditioning and pools. Ask how a property is cared for through the wet season when it is empty. Our [seasons tool](https://www.thailandpropertyinvestor.com/tools/seasons) shows each area by month, and the [area matchmaker](https://www.thailandpropertyinvestor.com/tools/area-matchmaker) can weight weather against your other priorities. For the wider comparison, read [where to buy in Thailand](https://www.thailandpropertyinvestor.com/guides/where-to-buy-in-thailand). ## Questions ### Which months are driest in Phuket? December to March. Phuket Town averages 24 to 74 mm of rain a month from January to March, against 210 to 360 mm a month from May to October. November and April are transitional. ### Is Koh Samui's weather different from Phuket's? Yes. Koh Samui's heavy rain falls from October to December, when Phuket is drying out, and Samui stays comparatively dry through the middle of the year, when Phuket is at its wettest. February to April is the driest period on Samui. ### What is the burning season? It is the late dry season in northern Thailand, roughly February to April, when crop burning, forest fires and land clearing fill the valleys with smoke. On 16 April 2026 Chiang Mai was among the ten most polluted major cities in the world. ### Which part of Thailand has the least rain? Of the main resort areas, Hua Hin. It averages about 936 mm a year, with only October exceeding 200 mm. Pattaya is next at about 1,106 mm. ## Sources - [Wikipedia, Climate of Thailand (Thai Meteorological Department seasons and monsoons)](https://en.wikipedia.org/wiki/Climate_of_Thailand) - [Wikipedia, Phuket province (Thai Meteorological Department normals 1981 to 2010)](https://en.wikipedia.org/wiki/Phuket_province) - [Wikipedia, Krabi (Thai Meteorological Department normals 1981 to 2010)](https://en.wikipedia.org/wiki/Krabi) - [Wikipedia, Ko Samui (WMO climate normals 1991 to 2020)](https://en.wikipedia.org/wiki/Ko_Samui) - [Wikipedia, Hua Hin (NOAA climate normals 1991 to 2020)](https://en.wikipedia.org/wiki/Hua_Hin) - [Wikipedia, Pattaya (WMO climate normals 1991 to 2020)](https://en.wikipedia.org/wiki/Pattaya) - [Wikipedia, Chiang Mai (WMO climate normals 1991 to 2020)](https://en.wikipedia.org/wiki/Chiang_Mai) - [IQAir, Chiang Mai among top 10 most polluted cities in the world, 16 April 2026](https://www.iqair.com/newsroom/chiang-mai-among-top-10-most-polluted-cities-in-the-world-4-16-2026) - [UK Government, Thailand travel advice, safety and security](https://www.gov.uk/foreign-travel-advice/thailand/safety-and-security)