The favorable tropical climate in Thailand is what ensures a pleasant stay throughout the year. Even here, however, it is necessary to take into account the changing seasons and humidity between 50 and 80%. The three seasons are divided into cool, hot and monsoon.
The average temperature in the 'cool' season (November-February) is 26 °C, while in the hot season (February-May) it is about 36 °C. The rainy season is warm and very humid, with up to 1,500 mm of rain falling and an average temperature of 32 °C. Tourists need not worry about this period. The rain often lasts only very briefly or overnight.
Compared to other dry and rainy season destinations, in Thailand (and SE Asia in general), it is not the case that you only experience nasty weather full of thunderstorms and rain during the monsoon season. So don't be afraid to go to Thailand in the off-season, the chances of good weather are still very high and conversely the chances of natural disasters associated with the monsoon (major flooding etc) are low.
In Bangkok, you have to take into account the heavily polluted air and smog that creates the greenhouse effect. Transitions from air-conditioned areas of buildings (16 °C-21 °C) to the open air place considerable demands on the body and health.
Below we describe what the average weather in Thailand usually looks like by month of the year. However, it is important to note that the description will never be 100% and just as you may get several showers during the high season, the sun may shine continuously during the monsoon season.
Looking at a geographical map of Thailand, it will also be clear to the more knowledgeable that the climate is not the same throughout the country, but varies noticeably within the west and east coasts of the Malay Peninsula. The two coastlines are often separated by only low tens of kilometres.
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Regions of Thailand with different climates
Thailand can be divided into 6 zones with slightly different climates and weather.
- Bangkok and surrounding areas - hot weather all year round, very muggy around May and June, monsoon season greatest during September and October
- West coast of the Malay Peninsula (Phuket, Krabi) - stable hot weather all year round, strong monsoon season from May to October
- East coast of the Malay Peninsula (Ko Samui) - stable hot weather all year round, on average a few degrees cooler than the west coast, rainfall moderate almost all year round, significant torrential rains from October to December
- Central and northern Thailand - stable temperatures throughout the year, wetter season during summer, but rainfall is not as heavy
- Border mountains in the north - cooler and very pleasant weather in winter, while significant monsoon season during summer
- East Coast (Trat, Chanthaburi) - also called the "Rainy Coast" due to the very significant monsoon season from June to October with heavy downpours
Thailand during the year
What is the weather like in Thailand in each month?
Weather in January
January is the peak season across virtually all of Thailand with the highest chance of great weather. Average temperatures across Thailand hover around 27°C, with Bangkok and central Thailand typically the warmest. However, relative humidity is at its lowest level of the year, so the heat is bearable.
Rainfall in January is at the lowest levels in the country. Slightly more rain is likely on the east coast (Koh Samui, Surat Thani) especially in early January, but it's nothing to plan a holiday here for. The sun will be shining for most of your stay.
In the north in Chiang Mai, temperatures can drop below 17°C overnight, so packing warmer clothing is a good idea.
Where to go: all of Thailand
Weather in February
Even February is good weather throughout Thailand. Compared to January, it's warming up a bit and temperatures can normally reach over 33°C in Bangkok or central or northern Thailand, but the lower humidity makes these temperatures bearable.
In beach destinations in the south, both the Andaman Sea and the Gulf of Thailand coasts are good to visit. It showers an average of 4 days a month, mostly afternoon showers that won't particularly disrupt your holiday. Temperatures on the west coast hover around 30°C, while on the east coast it's around 27°C.
Where to go: all of Thailand
Weather in March
March is a good time to visit the whole of Thailand. Bangkok, central and northern Thailand and the west coast of the Andaman Sea are the warmest - around 32 °C - while the east coast and Pattaya have temperatures around 3 degrees more comfortable.
Humidity is kept at acceptable levels, as is rainfall. On average, the east coast (Gulf of Thailand) receives the most rain, but it is still only about 4-5 days per month, and the vast majority of these are only evening heavy but short showers.
Where to go: all of Thailand
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Weather in April
In April, the hot pre-monsoon season begins to take full effect. This is marked by rising temperatures and especially humidity. This increase is most noticeable in and around Bangkok and also in the very east of Thailand near Koh Chang Island. In these areas, temperatures soar above 34 °C and the overall climate is very sultry.
In the south in the beach destinations, the weather tends to be a little more bearable with temperatures between 30 and 33 °C (warmer on the west coast).
Rain showers in Bangkok, Chiang Mai or off Koh Chang Island in eastern Thailand are still at low levels. There is a little more rain on the east coast of the Malay Peninsula, but still below average for the year.
Most of the rain is around Phuket, with showers every other day on average, but usually for an hour or two in the afternoon or night, so even on the west coast the rainfall won't affect holidays dramatically.
Where to go: all of Thailand
Weather in May
May is the peak month of the hot season before the monsoon. Temperatures range between 32 and 35°C across Thailand, with Bangkok and the surrounding area being the most uncomfortable to stay in due to the high humidity and smog. The air is literally soaked with water, but prolonged all-day rains are rather rare, with downpours usually starting after 4pm.
Moreover, statistics show May is not one of the rainiest months, and on the east coast of the peninsula, for example, there is a much better chance of fine weather than rain during the day. Even on the west coast it often only rains in the afternoon, albeit heavily and violently, but for 3-4 hours at most.
Where to go: the east coast of the Malay Peninsula(Koh Samui, Koh Tao and others) , the north of Thailand(Chiang Mai), but also the west coast(Phuket, Krabi and surroundings)
Weather in June
After the first half of June, temperatures drop slightly again, but still remain at around 32 °C throughout the country, even 34 °C in Bangkok and the surrounding area.
Statistically, the least rainfall (not even every other day) is expected on the east coast of the Malay Peninsula of the adjacent islands, the most on its west coast and then in the very east of Thailand and in the area of Trat and Koh Chang.
Where to go: east coast of the Malay Peninsula(Koh Samui, Koh Tao and others), north of Thailand(Chiang Mai)
Weather in July
Despite many assumptions that the summer holidays are not a great time to visit Thailand, the reality is somewhat different. Although temperatures and humidity are high (30 to 33°C), so especially in the cities can be quite uncomfortable, but in terms of rainfall, July is not one of the months during which it is impossible to travel.
On the contrary, the entire east coast of the peninsula with the adjacent islands (Ko Samui and others) enjoy mostly semi-cloudy weather with occasional evening thunderstorms, but these will have little effect on the stay. It's similar in the north in Chiang Mai, and the west coast can be enjoyed as well, although here the storms are more intense and sometimes start in the early afternoon.
Where to go: east coast of the Malay Peninsula(Koh Samui, Koh Tao and others), north of Thailand(Chiang Mai)
Weather in August
August marks the onset of Thailand's main monsoon season, but even during this time there are areas you can travel to without fear. Temperatures and general being outdoors is not as uncomfortable as during May. Morning showers are tempered by afternoon thunderstorms, with temperatures holding steady between 32 and 34°C throughout Thailand, dropping to as low as 24°C during the rains and at night.
The east coast of the peninsula receives the least rain, with evening showers only about every other day. In other areas of Thailand, the rain is more intense, but it certainly can't be said to fall from the sky all day long. Rather, expect short, heavy showers interspersed with sunny and partly cloudy weather.
Where to go: east coast of the Malay Peninsula(Koh Samui, Koh Tao and more)
Weather in September
September is the main rainy season in Thailand. The rains are heaviest in the Bangkok area and the west coast(Phuket, Krabi, etc.) and also in the east near the Cambodian border (Trat, Koh Chang) where the rainfall is most intense. Even during September, however, it may not rain every day in these areas, and certainly not all day. Although there are a lot of clouds in the sky, and showers can be expected at any time, but all-day long rains are rare and, at least for travel, September is not a bad month.
Moreover, the east coast of the Malay Peninsula gets significantly less rain and you can easily spend a typical beach holiday here.
Normal temperatures are not too different from the rest of the year and across Thailand, ranging between 30 and 33°C, but can drop to 24-25°C during rainfall.
Where to go: east coast of the Malay Peninsula(Koh Samui, Koh Tao and others), but also north around Chiang Mai
Weather in October
October is the final month of the monsoon season for most of Thailand, but rainfall does not occur to any great extent until the end of October. The weather is very similar to September, only statistically slightly less rain falls, with the exception of central-northern Thailand in the Chiang Mai area, when the rainy season recedes much more significantly.
In contrast, the east coast of the peninsula and the adjacent islands are slowly getting into the rainy season, but so far during October this usually means only more frequent and stronger thunderstorms in the afternoon.
Temperatures remain stable and stay above 30 °C.
Where to go: north around Chiang Mai, Malay Peninsula - Koh Samui, Koh Tao, Phuket, Krabi and other resorts (plus or minus both coasts, frequent but short showers)
Weather in November
During November, the weather often changes as if by magic. Regular afternoon thunderstorms are here and there, the skies are partly cloudy and temperatures drop to more comfortable values between 28 and 30°C. In addition, the humidity drops significantly, making being outside downright pleasant.
In November, the season starts practically all over Thailand. The exceptions are the east coast of the Malay Peninsula and the islands (Ko Samui, etc.), where, on the other hand, the rainy season begins in earnest. Particularly in November there is a high chance of torrential downpours on the east coast. However, just travel a few dozen kilometres to the other coast and you are likely to enjoy beautiful sunny weather.
Where to go: all of Thailand except the east coast of the peninsula
Weather in December
December is one of the best weather months, along with January and February. Even during this month, afternoon showers can occur, but the likelihood is incomparably lower than the rest of the year. Temperatures across the country stay at a comfortable 27-29 °C and humidity is not extreme.
The only rainy area is the east coast of the Malay Peninsula, when the rainy season ends. Heavy downpours can still occur early in the month, but these gradually diminish towards the end of the year.
Where to go: all of Thailand except the east coast of the peninsula
Sea temperature in Thailand
While the weather in Thailand varies quite dramatically across the year, the temperature of the sea water, whether you're on the east or west coast, remains more or less constant.
In the coldest winter months, you will bathe in 29 °C warm water, while in the hot summer heat the sea temperature will be around 31 °C. The differences are therefore really negligible and practically not noticeable.
Table of temperatures during the year
Thailand - Bangkok and surroundings - Temperatures and seasons during the year
Phuket, Krabi and the west coast - Temperatures and seasons during the year
Koh Samui, Surat Thani and East Coast - Temperatures and seasons during the year
Chiang Mai - north of Thailand - Temperatures and seasons during the year
Thailand - sea temperature - Similar values for the whole country
When to go to Thailand
Although the seasons in Thailand are distinctive, the country can be visited in virtually any season. A great advantage is the fact that even during the monsoon season it usually doesn't rain all day and if you don't mind the clouds in the sky, you can travel just fine. Precipitation is most prevalent in the afternoon and night hours.
The most ideal time to visit is during the cold season, between November and February. The climate is much more pleasant, less humid with minimal rainfall, and temperatures are more bearable for our people. This time of year can be described as the peak season, when Thailand is visited by the most tourists. It is therefore necessary to take this fact into account and be prepared for often extreme crowds in well-known places.
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During the monsoon and rainy season, you'll have the best chance of beautiful holiday weather along the east coast of the Malay Peninsula and on the islands of Koh Samui, Koh Lanta or Koh Tao. The advantage of travelling in the low season (May to October) is that there are noticeably fewer tourists and significantly cheaper accommodation. You also have a better chance of snagging bargain tickets.