Thailand has a warm tropical climate and high temperatures and high humidity are experienced throughout the year. The year can be divided into three distinct seasons:
March to the end of May sees very high temperatures and is known as the hot season. Temperatures can become uncomfortably hot, especially in the early afternoon. This season can see thunderstorms later on in the afternoon due to the build up of humidity, but these can often be a welcome relief.
The monsoon or rainy season runs from June to October. During this time, it is usual to experience rain everyday although this may be limited to just a 20 minute downpour which is refreshing and clears the high humidity. On the other hand it can rain solidly for several days especially in August, September and October when some parts of the country can suffer flooding.
The cool or winter season runs from November through to February and is much favoured by western visitors as there is generally a cooling north east breeze and lower humidity.
The north and north-east are generally cooler in winter and hotter in summer than central Thailand. The south of Thailand is less subject to changes than the rest of the country and has a generally has a shorter wet season.