Thailand is an all year round tropical destination even though you will find that the climate varies throughout the country. In general, the weather is hot and humid across most of the country throughout the year.
The weather in northern Thailand:
The weather in central, northern and northeastern Thailand is determined by three seasons: The dry and cool season lasts from November to February whereas the dry and hot season occurs from March to May. The rainy season starts in May and ends in November and is dominated by the southwest monsoon, during which time rainfall in most of Thailand is the heaviest.
The weather in southern Thailand:
The southern, coastal region of Thailand really has only two seasons – rainy season and dry season. Fortunately, for those planning a beach holiday, Thailand’s two coasts have slightly different rainy seasons, allowing visitors to find sunny beaches nearly year round.
On the Andaman or west coast, where Phuket, Krabi, and the Phi Phi Islands lie, the southwest monsoon brings heavy storms from April to October, while on the Gulf of Thailand or east coast, where Koh Samui, Koh Phangan, and Koh Tao are situated, the most rain falls between September and December.
January to March
The most popular season for tourists to travel to Thailand because of the lower temperatures while the chance for rain is little. This month usually brings a lot of sunshine to the beaches on the west coast. There may be a little bit of rain on Thailand’s east coast.
April to June
When you visit Thailand in April, expect to see more tourists as April is still considered high season. The traditional Songkran Festival (Thai New Year) takes place all over the country from 13 to 15 of April. This is a great time to travel if you are looking for the extra fun but not if you are looking for a bargain.
Even though historically May and June may not be seen as the best months to visit Thailand, we highly recommend to travel to Thailand during this time as you can take advantage of lower accommodation rates due to the shoulder season. The weather during these months is sunny with only a little chance of rain. When visiting beaches, make sure to choose a beach destination on the east coast.
July to September
While the beginning of July is still a good time to travel to Thailand and the sun is still out on the beaches of the east coast, August and September are the wettest months of the year. If you are looking for a beach holiday, you can make a good bargain but stick to the islands in the Gulf of Thailand on the west coast.
October to December
While rainfall can occur from time to time in October; November and December are excellent months to visit Thailand as it is sunny, relatively cool and dry in most places. Beware of the festive season at the end of December when most hotels charge a holiday surcharge.