Country-wide, September tends to be the wettest month of the year in Thailand with all corners of the country receiving rain in varying amounts. Temperatures continue to decline gradually throughout the month (avg temp: 25- 9°C) and thunder storms are not unusual as the humidity reaches its peak.
Beach conditions are generally poor with heavy rain and rough seas experienced on the west coast (Phuket, Krabi, Khao Lak) and increasingly heavy rains in Koh Samui and Koh Pha Ngan on the south east coast. If you feel lucky then the resorts of Hua Hin & Cha Am are likely to offer the best beach conditions across the country.
September is one of the wettest months in Khao Sok National Park, so take suitable waterproof clothing if you plan to visit this month. Don’t be put off by the rain: average temperatures during the month are a comfortable 25-26°C, the rainforest is green & lush, and there is more chance of spotting wildlife.
It's not all bad news: visitor numbers are (unsurprisingly) far lower than in previous months and low season hotel deals can be had.
A journey through northern Thailand for an eco-focussed exploration of local Lahu traditions and culture in the hills of Chiang Mai.