Weather in Thailand in March: where to swim and where there is smog

In March, Thailand changes seasons. The dry winter period is already over, and the monsoon rains have not yet begun, so the first half of the month remains almost ideal for beaches.

If you are flying for sea and sun, aim for Phuket and Pattaya. In Phuket, the water in March averages 29.6 °C (As of 09/2026, seatemperature.info), and daytime air stays around 31 °C (As of 09/2026, weather-and-climate.com). Bangkok and Chiang Mai are less suitable: the capital is stuffy and hot even at night, and the north is entering smog season. Below, we break down the weather by resort and suggest where you should go.

What the weather is like in Thailand in March

💡 In short:

• The dry season is ending, and prolonged rains begin only in May.
• In the first two weeks of the month, beaches stay dry; after that, downpours become more frequent.
• Phuket and Pattaya are better for a vacation in March than Bangkok and Chiang Mai.

Thai March sits at the junction of two seasons. The cool and dry period that makes the country popular from November is already over, and prolonged tropical rains will begin only in May. You land in a short window when the sea is calm and there is almost no rainfall.

Phuket in March: hot and humid

Phuket remains the country's most popular beach destination. Daytime air reaches 31 °C, and at night it rarely drops below 27 °C (As of 09/2026, weather-and-climate.com). Humidity is rising, so the heat feels stronger than in winter.

© JULIANISME · CC BY-SAPhoto: JULIANISME, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

The first half of the month is usually dry. Over the whole of March, the island receives about 94 mm of precipitation, and almost all of it falls in the last two weeks (As of 09/2026, weather-and-climate.com). Downpours are short: heavy rain lasts an hour, and then the sun comes out again.

If you want steady weather, take the first half of March. The water at that time averages 29.6 °C (As of 09/2026, seatemperature.info), and swimming is comfortable even in the evening. In the second half of the month, the sea can get choppy, but it is still warm for snorkeling.

Bangkok in March: stuffy and very hot

In Bangkok, March opens the hottest period of the year. During the day the air scorches, and at night it barely cools down, so you will be looking for coolness in shopping malls and parks.

© Preecha.MJ · CC BY-SAPhoto: Preecha.MJ, CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0), Wikimedia Commons

There is no sea in Bangkok, so the city is not suitable for a beach vacation: people use it as a two-day base for temples and markets, and then head to the coast.

• Who it's for: a short cultural stop on the way south.
• Not for: a long beach vacation, there is no sea here.

Pattaya in March: milder than Bangkok

Pattaya handles the heat more easily in March than the capital. Temperatures here are a few degrees lower than in Bangkok, and the sea breeze makes evenings more comfortable.

Pattaya gets more rain than Bangkok, but the downpours here are short, usually in the afternoon. They will not ruin a full vacation, and within an hour it is bright again.

© Sergey S. Dukachev · CC BY-SAPhoto: Sergey S. Dukachev, CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0), Wikimedia Commons

If you want a beach and a city in one resort, Pattaya fits.

• Who it's for: those who want a warm sea close to the city.
• Not for: those seeking solitude: in March it is still crowded here.

Chiang Mai in March: dry and smoky

In March, Chiang Mai remains a popular city in the north, but there is no beach vacation here: people come for temples, mountains and markets.

© Yimsurawut · CC BY-SAPhoto: Yimsurawut, CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0), Wikimedia Commons

The main reason to postpone Chiang Mai to another month: smog. From February to April, fields and forests are burned in the northern provinces, and smoke accumulates in the valley. In March 2026, the air in the city was rated at 233 AQI, and it ranked first in the world for pollution (As of 09/2026, asiabylocals.com).

If you are sensitive to dust and the smell of burning, March is a bad choice for the north. It is better to plan the trip for November or December, when the rains have already ended and the smoke has not yet arrived (according to Chiang Mai Brief).

What to pack in March

Bring light cotton clothing, high-SPF sunscreen and a hat: the sun in March is strong even on cloudy days.

In the second half of the month, pack a compact raincoat if you are planning Phuket or Pattaya. For the north, add a respirator, because the air in Chiang Mai can be dirty.

⁉️🤔 Frequently asked questions

What is the water temperature in Phuket in March?

The water off Phuket in March averages 29.6 °C, on some days up to 30 °C (As of 09/2026, seatemperature.info). Swimming is comfortable both morning and evening, and in the first half of the month the sea is usually calm. Warm water lasts all March, so you will not need a wetsuit.

When does the dry season end in Thailand?

The dry and cool season lasts from November to February. Already in March, humidity rises, and in the second half of the month the first downpours begin. It gets truly rainy in May, when the southwest monsoon arrives. So you get a short transitional window with a warm sea and rare rains.

Should Chiang Mai be included in a March itinerary?

Chiang Mai is better postponed if you are sensitive to air quality. From February to April, the north has a smog season. If the north is in your plans, choose November or December.

Where in Thailand gets the least rain in March?

In the first half of March, rain is rare almost everywhere. By the end of the month, the south, including Phuket, gets the most precipitation, while Pattaya and central areas get less. If dry days matter to you, plan your trip for the first two weeks of the month.

Which resort should you choose for a beach vacation in March?

For calm seas and snorkeling, take Phuket in the first half of March. Pattaya works if you want to combine the beach with the city and evening walks. Leave Bangkok as a short stop along the way, and move Chiang Mai to another season.

In short: where to go in Thailand in March

March weather divides Thailand into two groups. Phuket and Pattaya offer a warm sea and dry days, while Bangkok and Chiang Mai are harder to handle because of heat and smog.

• If you want a beach: take Phuket in the first half of March.
• If you want a beach near the city: look at Pattaya.
• If you are going for temples: give Bangkok two days.
• If you were planning Chiang Mai: move the trip to November or December.

Plan your vacation in advance and check the forecast before departure to catch the dry days.