Month 9 of 12
September is the wettest month on the southern west coast according to TMD/LDD; Maya Bay is closed through 30 September. Regions that score 'good' on rainfall in our overview: Koh Samui, Koh Phangan, Koh Tao. Regions with less suitable weather include Similan, Surin and Koh Rok (marine parks); Phuket, Phang Nga, Krabi; Ranong (Koh Phayam); and Trang and Satun (Koh Lipe). Average rainfall ranges from 104 mm (Prachuap Khiri Khan) to 816 mm (Trat). Below you will find 8 beaches, 8 islands, 8 festivals and holidays, 5 temples and 8 birds for September.
September is the wettest month on the southern west coast according to TMD/LDD; Maya Bay is closed through 30 September. Average rainfall: Phuket 361 mm, Krabi 275 mm, Koh Samui 118 mm, Hua Hin 130 mm, Pattaya 214 mm, Trat 816 mm.
Indication: the weather varies from year to year.
Average monthly rain per weather station; the bar runs from 0 to 1024 mm (the wettest month in this overview). Colour = our score for that region.
Not recommended🌊 rough sea
Very wet: Phuket (Mueang) 361 mm on 22.1 rainy days (monthly average). Sea: rough sea, red flags possible (SW monsoon May-Oct). Similan and Surin are closed to tourism 16 May to 14 October (2026: reopened 15 Oct); Koh Rok (Mu Ko Lanta NP) is also closed in the monsoon season.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th, nationthailand.com, siamtourandrealty.com, tatnews.org
Not recommended🌊 rough sea
Very wet: Phuket (Mueang) 361 mm on 22.1 rainy days; Krabi 275 mm on 18.5 rainy days (monthly average). Sea: rough sea, red flags possible (SW monsoon May-Oct). Maya Bay is closed to landings 1 August to 30 September. DMCR lists Phuket beaches (e.g. Kata, Karon, Patong, Kamala, Nai Harn) as high-risk for big waves and rip currents May to October.
Sources: en.wikipedia.org, en.wikipedia.org, en.sme.go.th, www1.ldd.go.th, asiantrails.travel, warning.dmcr.go.th, tatnews.org
Not recommended🌊 rough sea
Very wet: Ranong 679 mm on 22.8 rainy days (monthly average). Sea: rough sea, red flags possible (SW monsoon May-Oct).
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Not recommended🌊 rough sea
Very wet: Satun 334 mm on 17.3 rainy days (monthly average). Sea: rough sea, red flags possible (SW monsoon May-Oct). In Tarutao National Marine Park the Adang-Rawi islands and dive sites are closed 1 June to 30 September (DNP 2026 notice); Koh Tarutao and Koh Lipe stay open. Fewer boats from Pak Bara 1 June to 15 Oct.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th, nationthailand.com, thainationalparks.com, ploysiamspeedboat.com
Good🌊 calm sea
Relatively dry: Ko Samui 118 mm on 10.6 rainy days (monthly average). Sea: sea mostly calm.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Fair🌊 calm sea
Changeable: Chumphon 179 mm on 15.4 rainy days (monthly average). Sea: sea mostly calm.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Fair🌊 variable sea
Changeable: Hua Hin 130 mm on 10.6 rainy days; Prachuap Khiri Khan 104 mm on 9.9 rainy days (monthly average). Sea: changeable sea in the wet season.
Sources: en.wikipedia.org, en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Fair🌊 variable sea
Changeable: Pattaya 214 mm on 13.2 rainy days; Chonburi 280 mm on 16.3 rainy days; Sattahip 244 mm on 14.6 rainy days (monthly average). Sea: changeable sea in the wet season.
Sources: en.wikipedia.org, en.wikipedia.org, en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Fair🌊 variable sea
Changeable: Rayong 269 mm on 14.6 rainy days (monthly average). Sea: changeable sea in the wet season.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Not recommended🌊 rough sea
Very wet: Chanthaburi 538 mm on 21.6 rainy days (monthly average). Sea: rougher sea and fewer boat services in the wet season. No Chanthaburi beaches or islands in our list; climate only.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Not recommended🌊 rough sea
Very wet: Trat 816 mm on 22.5 rainy days (monthly average). Sea: rougher sea and fewer boat services in the wet season. Koh Mak and Koh Kood have fewer boats in the wet season; speedboats often stop. Trat is one of the wettest provinces in Thailand (>4,000 mm a year, LDD).
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th, visit-thailand.org
Not recommended
Very wet: Bangkok 336 mm on 18 rainy days (monthly average). Bangkok climate used as a proxy for Koh Kret.
Sources: en.wikipedia.org, en.sme.go.th, www1.ldd.go.th
Regions scored not recommended:
Beaches at their best in Septemberℹ️ The season score is based on average rainfall and the climate per region, not on a weather forecast. It is not a guarantee: the weather varies from year to year.
Festivals and holidays in September8 of the 9 festivals in our festival list that can fall in September.
📍 Nakhon Si Thammarat town
📍 Phraya Phichai Dab Hak sports field, Uttaradit
📍 Nan River at Wat Tha Luang, Phichit
📍 Ban Sam Yaek, Mae Salong, Mae Fah Luang
📍 Nan River, Nan city
📍 Jui Tui Shrine and Phuket Town
📍 Yaowarat Road (Chinatown), Bangkok
📍 Haad Rin, Koh Phangan
Temples to visit in September📍 Bangkok (Phasi Charoen)
Silver Temple
📍 Chiang Mai (Wualai)
Ajahn Chah monastery
📍 Warin Chamrap, Ubon Ratchathani
📍 Bophut, Ko Samui
📍 Phetchaburi
Birds to see in SeptemberIn our bird guide, 6 species have September in their best season, of which 1 are winter visitors or passage migrants; 56 species are present year-round. This follows from the best season listed for each species.
Hotels at beaches and islands that are good in SeptemberHotels listed on our beach and island pages, at a place that scores well this month.
€€ at Haad Salad
⏰ Check whether the hotel is open this month.
€ at Sairee Beach
⏰ Check whether the hotel is open this month.
€€€ at Maenam Beach
⏰ Check whether the hotel is open this month.
€€ at Haad Yuan
⏰ Check whether the hotel is open this month.
€ at Haad Khom (Coconut Beach)
⏰ Check whether the hotel is open this month.
€€€ at Bophut Beach (Fisherman's Village)
⏰ Check whether the hotel is open this month.
September is the wettest month on the southern west coast according to TMD/LDD; Maya Bay is closed through 30 September. Average rainfall: Phuket 361 mm, Krabi 275 mm, Koh Samui 118 mm, Hua Hin 130 mm, Pattaya 214 mm, Trat 816 mm. Indication: the weather varies from year to year.
Based on average rainfall: Koh Samui, Koh Phangan, Koh Tao. Good beaches this month include Silver Beach (Crystal Bay / Thong Ta Khian), Koh Nang Yuan and Thong Nai Pan Noi.
Examples: Sart Duan Sip (Tenth Month Festival) (expected mid-September to early October 2027); Uttaradit Langsat Festival (expected in September 2027); Phichit Long Boat Races (expected in September 2027); Akha Swing Festival (expected in September 2027); Nan Boat Races (expected in September 2027). Many festivals follow the lunar calendar or are set locally each year, so dates shift.
Islands at their best in September