May in Thailand is hot and humid, with the first hints of the rainy season. Expect warm sunny days and the occasional short tropical shower, especially in the south.
It's still not full monsoon, so beaches, islands, and national parks remain very enjoyable.
May is also a quieter shoulder season. It's a great time to explore the country with a crowd-free experience and lower costs.
If you're deciding where to go, what to pack, or whether May is right for you, keep reading—I'll walk you through everything you need for a smooth trip.
Thailand's Weather and Climate in May
May is a challenging time to visit Thailand. The weather is hot and humid, and you'll catch the start of the rainy season with frequent afternoon showers.
In May, most of Thailand experiences hot and sticky weather, with temperatures averaging 26-33°C (79-91°F). It's the tail end of the hot season, so expect to sweat even in light, breathable clothing.
If you're heading north to Chiang Mai, it's slightly cooler in the mornings, ranging from 24-34°C (75-93°F). Packing light cotton clothes and a rain jacket is smart.
Down south in Phuket, it already feels like full rainy season, with highs around 32°C (90°F) and humidity at 79%.
Rain becomes a real factor in May. Most regions get around 14-16 rainy days, with the official rainy season starting mid-month on May 15th. Showers are typically short but intense, usually hitting in the late afternoon or evening. Mornings are often still sunny, making them the best time for sightseeing.
Bangkok and Central Thailand in May: Hot but Vibrant
Wat Pho in BangkokExpect hot and humid weather in May in central Thailand cities like Bangkok, Ayutthaya, and Pattaya.
The average temperatures range from 26-33°C (79-91°F), with midday heat often reaching 34°C (93°F). You'll feel the heat intensely during the day, while evenings offer little relief.
May is moderately rainy in Bangkok. The city gets around 14-16 rainy days, with sudden downpours in the late afternoon. However, the rain usually clears up within an hour or two, and mornings remain mostly sunny.
Plan outdoor activities for early morning or late evening. Save midday for air-conditioned malls, museums, or cooking classes. Bangkok's night markets and rooftop bars offer the best way to experience the city after sunset.
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Join our popular 12-Day Thailand Tour covering Bangkok, Chiang Mai, and Koh Samui. Our travel experts will customize it to your interests, ensuring you experience the best of Thailand while staying comfortable in the heat.
Chiang Mai and Northern Thailand: Cooler
Doi Inthanon in Northern ThailandIn May, Chiang Mai in northern Thailand is slightly cooler than the rest of the country. The temperature ranges from 24-34°C (75-93°F), with mountain areas offering refreshing morning breezes.
The region gets around 14-15 rainy days, but showers are usually brief and occur in the late afternoon. This makes mornings perfect for temple visits and outdoor exploration.
Chiang Rai is usually a touch cooler than Chiang Mai, especially at night, while Pai brings that crisp mountain start to the day, sometimes dipping to 20–22°C (68–72°F)before the sun warms everything up. Mae Hong Son stays warm but with lighter humidity.
Southern Thailand Islands: East Coast vs West Coast
Koh SamuiSouthern Thailand has two distinct coastlines with opposite weather patterns in May.
West Coast (Phuket, Krabi) - Rainy Season Begins
The West Coast, including Phuket, Krabi, and Phi Phi Islands, enters its rainy season in May. Temperatures reach 32-34°C (90-93°F) with increasing rainfall and rough seas.
By late May, strong winds and waves make swimming unsafe at many beaches. National marine parks close after May, and diving visibility drops significantly.
East Coast (Koh Samui, Koh Tao) - Still Good Season
The East Coast enjoys excellent conditions in May. Temperatures range from 30-35°C (86-95°F) with only brief, occasional showers. The sea remains calm and clear.
Koh Tao is especially outstanding in May. This is peak diving season (March-May), with visibility reaching 15-30 meters—the best of the entire year. You'll have excellent chances of spotting whale sharks.
For May, the East Coast is the clear winner with better weather, calmer seas, and lower prices.
4 Best Places to Visit in Thailand in May
May brings tropical sunshine, lush landscapes, and fewer crowds—exactly the kind of Thailand you want before the monsoon fully arrives. Here are my top 4 destinations that shine in May.
1. Koh Samui: Best Beach Weather in May
Koh Tao near Koh SamuiIf you want proper beach days in May, Koh Samui is the spot.
While the Andaman Coast starts seeing early monsoon showers, Samui stays mostly dry thanks to its opposite weather pattern. Expect clear waters for snorkeling, gentle waves, and plenty of good days for island-hopping.
For the clearest water, I recommend spending at least one day around Koh Tao or Ang Thong Marine Park. May is usually the sweet spot before visibility drops later in the season.
2. Chiang Mai and Chiang Rai: Cool Mountain Escapes
White Temple in Chiang RaiNorthern Thailand in May offers a pleasant escape from the lowland heat. Mornings and evenings feel breezy.
In Chiang Mai, you can stroll through the old city, join a cooking class, or enjoy traditional cultural activities without the peak-season crowds. In Chiang Rai, the White Temple, Blue Temple, and Black House provide stunning photography opportunities in peaceful surroundings.
The lush landscapes around both cities are at their greenest in May, adding extra charm to any outdoor adventure.
If you want a true cool-down, head up to Doi Inthanon. May mornings can still feel refreshingly cool, and the viewpoints are often clearer before the monsoon sets in.
If possible, don't miss Vesak Day (May 11-12), one of Buddhism's most sacred holidays. At Doi Suthep Temple, you'll witness 700 monks in a traditional ceremony, followed by a candlelight procession at sunset.
3. Kanchanaburi: Waterfalls at Their Peak
Erawan FallsKanchanaburi looks its freshest in May.
The early showers bring fuller waterfalls, greener forests, and cooler river breezes, while the rain usually comes in short bursts.
This is the perfect time to enjoy Erawan Falls, light hikes, or a slow day by the river. The historical sites—like the Death Railway—also feel more peaceful without peak-season crowds.
4. Khao Sok National Park: Lush Rainforest
Khao Sok National ParkIf you love scenery, Khao Sok in May can be magical.
The rainforest turns deep green, limestone cliffs look dramatic after light rains, and Cheow Lan Lake often has mist drifting over the water in the early morning.
Boat trips feel quiet, wildlife is more active, and staying in a floating bungalow becomes a truly atmospheric experience.
Tell us what you enjoy, culture, nature, or both, and we can customize a tour based on your preference.
Crowds and Costs in Thailand in May
May is a great time to travel if you want to avoid the crowds. Popular spots like Koh Samui or Chiang Mai are still lively, but you'll find shorter lines, easier bookings, and a more relaxed vibe than in peak season.
Prices for hotels, tours, and transport are usually around 10–20% lower than the busy months.
Hotels aren't as fully booked as in peak season, but it's still a good idea to reserve island or mountain stays in advance if you want the best rooms.
What to Wear for Thailand in May
For Thailand in May, keep it light and breezy—cotton or linen tops, loose pants or skirts, and comfortable sandals. Bring a small raincoat or umbrella for occasional showers. A light shawl or cover-up is useful for temples.
If you plan to visit Doi Inthanon or other highland areas, a light jacket or long-sleeved shirt can be handy for cooler mornings and evenings.
FAQs about Thailand Weather in May
Q: How hot is Thailand in May?
Daytime temperatures are generally 30–35°C (86–95°F), and it's humid. Mountains and beaches may feel slightly cooler.
Q: Is it rainy in Thailand in May?
Showers are more common than in April, particularly in southern regions. Rain is usually short and tropical.
Q: Which island is best in Thailand in May?
Koh Samui is the best pick. Its Gulf-side location gives it drier weather in May. The Andaman coast (Phuket, Krabi) starts to see more showers.
Q: How cool does northern Thailand get at night?
In Chiang Mai and the mountain areas, nights drop to around 24°C (75°F), offering relief from daytime heat.
Q: Is May a good time to visit Thailand?
Yes! May is shoulder season, meaning fewer crowds and slightly lower prices than peak season. Beaches, mountains, and national parks are still enjoyable, and early showers rarely ruin your plans.
Ready to plan your May trip to Thailand?
Our clients in ThailandIf you want a route that stays dry, avoids the crowds, and hits the best beaches for this time of year, we can help you map it out. Tell us what kind of trip you're dreaming of, and we'll build a smooth, May-friendly itinerary for you.
You could also check out our Thailand tours for inspiration.
- 10-Day Classic Thailand Tour: Bangkok, Chiang Mai, and Koh Samui
- 12-Day Thailand Wonders Tour: Bangkok, Kanchanaburi, Chiang Mai, and Krabi
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