Thailand's climate can generally be described as tropical, however, due to the size of the country, averages do tend to vary a little bit depending on your location. Thailand's proximity to the equator means that temperatures usually remain stable throughout the year although November to February is normally a little bit cooler. Depending on where you are staying rainfall can vary, typically January to March are the driest months of the year, in Phuket rains start in May through to September while Koh Samui is wettest between October and November.
Thailand Climate Chart
Average Temperatures (°C) in Thailand throughout the year
Thailand Rainfall Chart
Average Rainfall (mm) in Thailand throughout the year