The best advice I can give is to travel as light as possible. The climate is basically hot and humid so it is best to wear loose or relaxed fitting clothing made from natural materials like cotton. During the cool season in the north it can get chilly in the evenings so a shawl or light jacket may be required.
Another good reason for packing a light jacket, is that the air-conditioning on some tour buses and trains can be quite fierce. Shorts, flip-flops and t-shirt may have seemed a good idea when you got on board, but 20 minutes into the journey you could be shivering from the air-con being turned up full blast by the driver.
You may end up having 2 or 3 different changes of clothes each day because of the heat and humidity, but laundry services are available in every town, city and resort offering a cheap and efficient service. If you do forget to pack something, clothing is extremely cheap in Thailand so just buy it when you’re over here.
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