Thailand’s favourable tropical climate ensures a pleasant stay all year round. However, visitors should still be prepared for the changing seasons and humidity levels ranging from 50 to 80 per cent. The three seasons are divided into the cool season, the hot season and the monsoon season.

Average temperatures during the ‘cool’ season (November–February) reach 26 °C, whilst during the hot season (February–May) they are around 36 °C. The rainy season is hot and very humid, with up to 1,500 mm of rainfall and an average temperature of 32 °C. Tourists need not worry about this season. The rain often lasts only a very short time or falls overnight.

Unlike other destinations with distinct dry and wet seasons, in Thailand (and Southeast Asia in general) it is not the case that you will only experience bad weather full of storms and rain during the monsoon season.

So don’t be put off visiting Thailand even out of season; the chances of good weather are still very high, whilst the risk of natural disasters associated with the monsoon (such as major flooding) is low.

In Bangkok, you should expect heavily polluted air and smog, which creates a greenhouse effect. Moving from air-conditioned indoor spaces (16 °C–21 °C) to the open air places considerable strain on the body and your health.

Below, we describe whatthe average weatherin Thailandis usually like, broken down by month. However, it is important to bear in mind that this description will never be 100% accurate; just as you may experience a few showers during the peak season, the sun may shine continuously even during the monsoon season.

Looking at a map of Thailand, it will also be clear to the more knowledgeable that the climate is not the same across the whole country, but varies noticeably even between the west and east coasts of the Malay Peninsula. Yet these two coastlines are often separated by just a few dozen kilometres.

Check flight prices to Thailand in the off-season

Regions of Thailand with different climates

Thailand can be divided into six zones, each with a slightly different climate and weather.

1. Bangkok and the surrounding area– hot weather all year round, very humid around May and June, with the monsoon season at its peak in September and October
2. The west coast of the Malay Peninsula (Phuket, Krabi)– consistently hot weather all year round, a pronounced monsoon season from May to October
3. East coast of the Malay Peninsula (Ko Samui) – consistently hot weather all year round; on average, it is a few degrees cooler here than on the west coast; rainfall is moderate throughout most of the year, with significant downpours occurring from October to December
4. Central and Northern Thailand– stable temperatures all year round; a wetter season during the summer, but rainfall is not usually as heavy
5. The border mountains in the north– cooler and very pleasant weather in winter, whilst the summer sees a significant monsoon season
6. The east coast (Trat, Chanthaburi) – also known as the ‘Rainy Coast’ due to very heavy monsoon seasons from June to October with torrential downpours

• 👉 Where to go in Thailand? My experience of the 4 regions

Thailand throughout the year

What is the weather like in Thailand in each month?

Weather in January

January is the peak season across virtually the whole of Thailand, offering the best chance of great weather. Average temperatures across Thailand hover around 27 °C, with Bangkok and central Thailand typically being the warmest. However, relative humidity is at its lowest level of the year, so the heat is bearable.

Rainfall in January is at its lowest levels across the country. There is a slightly higher chance of rain on the east coast (Ko Samui, Surat Thani), particularly at the start of January, but this is nothing that should stop you from planning a holiday here. You’ll enjoy sunshine for most of your stay.

In the north, in Chiang Mai, temperatures can drop below 17 °C at night, so it’s a good idea to pack some warmer outerwear.

Where to go:all over Thailand

Weather in February

February also brings good weather throughout Thailand. Compared to January, it gets slightly warmer and, for example, in Bangkok or central and northern Thailand, temperatures can commonly exceed 33 °C; however, thanks to lower humidity, these temperatures are bearable.

In the beach destinations in the south, both coasts – the Andaman Sea and the Gulf of Thailand – are ideal for a visit. It rains on average 4 days a month; these are mostly afternoon showers that won’t particularly disrupt your holiday. Temperatures on the west coast hover around 30 °C, whilst on the east coast they are around 27 °C.

Where to go:all over Thailand

Weather in March

March is a good time to visit the whole of Thailand. It is warmest – around 32 °C – in Bangkok, central and northern Thailand, and on the west coast of the Andaman Sea, whilst the east coast and Pattaya enjoy temperatures that are roughly 3 degrees cooler.

Humidity remains at acceptable levels, as does rainfall. On average, it rains most on the east coast (Gulf of Thailand), but this still amounts to only about 4–5 days a month; moreover, the vast majority of these are just heavy but short evening showers.

Where to go:all over Thailand

Book your hotel in Thailand in advance

Weather in April

April marks the start of the hot pre-monsoon season in earnest. This is characterised by rising temperatures and, in particular, high humidity. This increase is most noticeable in Bangkok and the surrounding area, as well as in the far east of Thailand near the island of Koh Chang. In these areas, temperatures can rise above 34 °C and the climate is generally very muggy.

In the south, at beach destinations, the weather tends to be slightly more bearable, with temperatures between 30 and 33 °C (it is usually warmer on the west coast). 

Rain showers in Bangkok, Chiang Mai and on the island of Koh Chang in eastern Thailand remain at low levels. It rains a little more on the east coast of the Malay Peninsula, but rainfall is still below average for the year.

It rains most around Phuket, with showers on average every other day, though usually for just an hour or two in the afternoon or at night, so even on the west coast, the rainfall won’t have a dramatic impact on your holiday.

Where to go:throughout Thailand

Weather in May

May is the peak month of the pre-monsoon heatwave. Temperatures across Thailand range from 32 to 35 °C; due to high humidity and smog, staying in Bangkok and the surrounding area is the most unpleasant experience. The air is literally saturated with moisture, but prolonged all-day rain is rather rare; downpours usually start after 4 pm.

Furthermore, statistically speaking, May is not one of the rainiest months, and on the east coast of the peninsula, for example, there is a much greater chance of fine weather than rain during the day. Even on the west coast, it often rains only in the afternoon – heavily and intensely, but for no more than 3–4 hours.

Where to go:theeastcoast of the Malay Peninsula (Koh Samui, Ko Tao and others), northern Thailand (Chiang Mai), and also the west coast (Phuket, Krabi and the surrounding area)

Weather in June

After the first half of June, temperatures drop slightly again, but still remain around 32 °C across the country, and as high as 34 °C in Bangkok and the surrounding area. There is also slightly less rainfall than in May, so June can be characterised as a sort of transitional period between the monsoons.

Statistically, the least rainfall (not even every other day) can be expected on the east coast of the Malay Peninsula and the adjacent islands; conversely, the most rainfall is on its west coast, followed by the far east of Thailand and the Trat and Koh Chang areas.

Where to go:the east coast of the Malay Peninsula (Koh Samui, Koh Tao and others), northern Thailand (Chiang Mai)

Weather in July

Despite the widespread assumption that the summer holidays are not the best time to visit Thailand, the reality is somewhat different. Whilst temperatures and humidity are high (30 to 33 °C), which can make a stay rather unpleasant, particularly in the cities, July is not one of those months where travelling is impossible due to rainfall.

On the contrary, the entire east coast of the peninsula and the neighbouring islands (Ko Samui and others) enjoy mostly partly cloudy weather with occasional evening thunderstorms, which, however, have little impact on your stay. The situation is similar in the north, in Chiang Mai, and it is also possible to visit the west coast, although the thunderstorms there are more intense and sometimes start as early as the early afternoon.

Where to go:the east coast of the Malay Peninsula (Koh Samui, Koh Tao and others), northern Thailand (Chiang Mai)

Weather in August

August marks the start of the main monsoon season in Thailand, but even during this period there are areas you can travel to without any worries. Temperatures and the overall experience of being outdoors are not as unpleasant as they are in May. The muggy mornings are cooled by afternoon thunderstorms, with temperatures remaining stable at between 32 and 34 °C throughout Thailand, dropping to as low as 24 °C during rain and at night.

It rains the least on the east coast of the peninsula, which is only hit by evening showers roughly every other day. In other parts of Thailand, the rain is heavier, but it certainly cannot be said that it rains all day long. On the contrary, expect short, heavy showers interspersed with sunny and partly cloudy weather.

Where to go:the east coast of the Malay Peninsula (Koh Samui, Koh Tao and others)

Weather in September

September marks the peak of the rainy season in Thailand. It rains most heavily in the Bangkok area and on the west coast (Phuket, Krabi, etc.), as well as in the east near the border with Cambodia (Trat, Koh Chang), where rainfall is at its heaviest. However, even in September, it does not necessarily rain every day in these areas, let alone all day long. Although the sky is often cloudy and a shower can be expected at any time, all-day, prolonged rain is rare, and, at least for travelling, September is by no means a particularly bad month.

What’s more, it rains significantly less on the east coast of the Malay Peninsula, so you can enjoy a typical beach holiday there without any worries.

Temperatures are not much different from the rest of the year and across Thailand, ranging between 30 and 33 °C; during rainfall, they can drop as low as 24–25 °C.

Where to go:the east coast of the Malay Peninsula (Koh Samui, Ko Tao and others), but also the north around Chiang Mai

Weather in October

October marks the end of the monsoon season for most of Thailand, although rainfall continues to a greater extent until the end of October. The weather is very similar to that in September, although statistically slightly less rainfall is recorded, with the exception of central-northern Thailand around Chiang Mai, where the rainy season is drawing to a much more marked close.

Conversely, on the east coast of the peninsula and the neighbouring islands, the rainy season is slowly setting in, although during October this usually just means more frequent and heavier afternoon thunderstorms.

Temperatures remain unchanged, staying above 30 °C.

Where to go:the north around Chiang Mai; the Malay Peninsula –Koh Samui, Ko Tao, Phuket, Krabi and other resorts (more or less the same on both coasts, with frequent but short showers)

Weather in November

During November, the weather changes frequently, as if by magic. The regular afternoon thunderstorms are a thing of the past; the sky is partly cloudy and temperatures drop to more pleasant levels between 28 and 30 °C. What’s more, the humidity drops significantly, making it a real pleasure to be outdoors.

The tourist season begins in practically the whole of Thailand in November. The exceptions are the east coast of the Malay Peninsula and the islands (such as Ko Samui), where, on the contrary, the heavy rainy season begins. In November in particular, there is a high chance of torrential downpours on the east coast. However, if you travel just a few dozen kilometres to the other coast, you’ll probably be enjoying lovely sunny weather.

Where to go:the whole of Thailand except the east coast of the peninsula

Weather in December

December, along with January and February, is one of the months with the best weather. Even during this month, afternoon showers may occur, but the likelihood is incomparably lower than during the rest of the year. Temperatures across the country remain at pleasant levels between 27 and 29 °C, and humidity is not excessive either.

The only area with more rain is the east coast of the Malay Peninsula, where the rainy season is drawing to a close. Heavy downpours may still occur here at the start of the month, but these gradually ease off towards the end of the year.

Where to go:the whole of Thailand except the east coast of the peninsula

Sea temperatures in Thailand

Whilst the weather in Thailand varies quite significantly throughout the year, the sea temperature – whether you’re on the east or west coast – remains more or less constant.

During the coldest winter months, you can swim in water at 29 °C, whilst during the sweltering summer heat, the sea temperature will be around 31 °C. The differences are therefore truly negligible and practically imperceptible.