Weather in Thailand in March

March climate overview

Daytime highs across Thailand in March run from 29.2°C (Koh Samui) to 34.2°C (Chiang Mai). In Chiang Mai about 99% of March days reach 25°C. Nights average 24.8°C; the coldest 10% of nights in Koh Samui fall to 25°C or below.

Rainfall in March

Expect around 9 rainy days (1 mm or more) in March, with Chiang Mai the driest (2 days) and Khao Lak the wettest (15 days). The wettest March at Chiang Mai between 1991 and 2020 was 2011 with 75 mm; the driest was 1992 with 0 mm.

Sea temperature

The sea averages 29.3°C around Thailand in March - warmest at Krabi (29.6°C). That is comfortable for swimming.

Sunshine and daylight

Around 6.2 hours of sunshine a day on average, out of 11.9 hours of daylight (sunshine estimated from cloud cover).

March against the rest of the year in Thailand

March is the 2nd warmest month of the twelve in Thailand. It is 1.1°C warmer than February and 0.4°C warmer in April. The hottest month here is April (32°C) and the coolest December (29°C).

Which part of Thailand in March?

• Most sunshine: Chiang Mai, 9.2 h a day.
• Driest: Chiang Mai, about 2 rainy days.
• Warmest sea: Krabi, 30°C.
• Hottest: Chiang Mai, 34°C by day - intense for sightseeing.
• Coolest (better for walking and cities): Koh Samui, 29°C.

What to pack for Thailand in March

Based on the averages: light, loose clothing and serious sun protection - midday highs sit around 32°C; a rain jacket - roughly 9 wet days; swimwear - the sea is 29°C.

Similar weather elsewhere in March

Within 1.5°C of Thailand's March daytime average: Guanacaste (33°C, sea 27°C), Goa (32°C, sea 29°C), Mombasa (31°C, sea 29°C), Kerala (31°C, sea 29°C), Kuala Lumpur (31°C). See the full ranking for March.

Chiang Mai and Bangkok: less rain, more daytime heat

Chiang Mai is the strongest choice here if avoiding rain matters most, with 2 rainy days compared with Bangkok's 6. Both reach 34°C by day, so neither offers much relief from afternoon heat. Plan longer walks for the morning and leave room for shade or an indoor break at midday. The bigger difference comes after sunset: Chiang Mai falls to 21°C, while Bangkok stays at 26°C. That makes Chiang Mai the better fit for travellers who want less rain and more comfortable evenings. Bangkok suits those comfortable with warmth that continues into the night; light clothing and a cool room will matter.

Choosing a coast: Koh Samui, Phuket, Krabi or Khao Lak

Koh Samui offers the lowest daytime temperature among these destinations at 29°C, with 9 rainy days. It is a sensible coastal choice if you prefer less intense daytime heat, though nights remain warm at 27°C. Phuket is slightly hotter at 30°C and has 11 rainy days, with sea temperatures also at 30°C. Krabi reaches 32°C, has 13 rainy days and shares Phuket's warm sea temperature. Khao Lak sits at 31°C but has the most rainy days of these choices, at 15, so it suits travellers willing to keep outdoor plans flexible. For a balance of lower daytime heat and fewer rainy days, Koh Samui stands out.

What the weather means for your day

March calls for light, breathable clothes, sun protection and a pace that leaves space for breaks. The country averages 6.2 hours of sunshine, so rain should not be your only packing concern. A light waterproof is sensible, particularly for the coastal destinations with more rainy days. Keep weather-sensitive plans flexible rather than relying on every day being dry. Sea temperatures of 29°C to 30°C make warm-water swimming a clear attraction on the coast, although temperature alone does not tell you about swimming conditions. Evenings are still warm in most of these destinations, so prioritise comfortable clothing and accommodation where you can cool down.