Climate in Thailand: change by month and region
The Kingdom of Thailand has two types of climate: the tropical one in the northern regions of the country and the tropical monsoon one in the southern and southeastern regions. Thus, weather conditions in Thailand vary significantly by month and region.
Length of seasons and average temperatures in Thailand
There is a saying popular among Europeans and Americans living in Thailand: «There are three seasons here: hot, very hot and unbearably hot.» The summer monsoon (sustained wind) dominates over the territory of Thailand from late April to mid-November, while the winter monsoon occurs from November to February.
Due to the monsoons, there are three climatic seasons in the northern, northeastern and central parts of the country:
- humid or rainy season (from late May to late October);
- cool dry season (from November to late February);
- hot dry season (from March to the end of May).
There are only two climatic seasons in the southern Thailand:
- dry season (from November to April);
- humid season (from May to October).
You can vacation in Thailand almost all year round. The hottest months are April and May, when air temperature usually rises above 35°C and even 40°C is not uncommon. The closer you get to the equator, the smaller the temperature difference will be. Cool season in Thailand lasts from December to February with an average air temperature of 20—27°C. In Pattaya, the mellow season happens in September and October; in Phuket — in September, October and November; on Koh Samui — in July, August and September.
Air temperature, °C
Water temperature, °C
Acclimatisation to tropical heat in high humidity conditions can take several days. If you are heading to the north of Thailand at the end of the dry season, be aware of the significant difference between day and night temperatures and remember to bring warm clothes.
Precipitation in Thailand
There is no universal rainy season for the whole country; the humid period lasts for 6–8 months on average. The heaviest rains traditionally fall in the central part of the country as well as on the east coast in August, September and October. More than 1,000 mm of precipitation falls on the Chao Phraya Lowland; up to 900 mm — on the northeastern Khorat Plateau; and from 3,000 to 5,000 mm — in the mountainous regions with heavy tropical showers.
The Kingdom of Thailand has a vast territory, so the rainy season in different regions of the country comes at different times. In Pattaya and Phuket it occurs in August and September; on Koh Samui — from mid-November to mid-December; on Koh Chang — in June and July; in Chiang Mai — in April and May. However, the monsoon season should not be considered unsuitable for holidays in the country’s seaside resorts. Rains at this time of the year tend to fall at night or early in the morning and last for 15–30 minutes; afterwards the sky clears up and comfortable, sunny weather sets in.
Insects in Thailand
It should be noted that there are many mosquitoes in Thailand. They are active at dawn and dusk, and are especially attracted to people who use body fragrances: perfumes, deodorants, and aftershave lotions. The further south you go, the more mosquitoes you will encounter due to the more humid climate. Apart from some areas bordering Myanmar and Cambodia, malaria is not considered a major problem in Thailand. Cases of Japanese encephalitis spread by ticks and mosquitoes have been reported in the northern and central regions of the country. In addition, there are many ants, cockroaches and spiders in Thailand that can make their way into houses.