When is the Rainy Season in Thailand?

The rainy season in Thailand varies from region to region and is largely dominated by the monsoon. Very broadly speaking, Thailand’s rainy season can be classified as May/June to October. For most of Thailand, the wettest months are usually August-October. However, the Gulf Coast of the southern peninsula (e.g. Ko Samui, Ko Pha Ngan) is affected by the south-west monsoon which can lead to heavy rainfall in November and the beginning of December.

Don’t be put off by the thought of visiting Thailand during the rainy season. Yes, the rain can be torrential, but the weather is still very warm and the downpours are often short and sharp. Bargains can be had with accommodation and the tourist areas are less crowded.

Average
rainfall (mm)
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Bangkok 11 28 31 72 190 152 158 187 320 231 57 9
Chiang Mai 8 6 15 45 153 136 167 227 251 132 44 15
Ko Samui 144 33 51 86 158 93 131 106 113 266 526 213
Pattaya 19 14 52 67 177 79 77 91 202 249 134 4
Phuket 42 30 60 157 345 286 284 272 417 351 188 71

Statistics from Thai Meteorological Department