Thailand in April: Weather, Crowds & What to Expect
Northern Thailand - including Chiang Mai and Chiang Rai - suffers heavy agricultural-burning haze from roughly February to April. Air quality can fall to unhealthy levels and mountain views are often lost to smoke. If you’re sensitive to air pollution, favour the southern islands and beaches during these months.
Climate Map for April
Average temperature across Thailand in April.
City Weather in April
| City | High | Low | Rain | UV | Feels |
|---|---|---|---|---|---|
| Bangkok | 35° | 26° | 62 mm | extreme | Hot |
| Chiang Mai | 36° | 22° | 49 mm | extreme | Hot |
| Udon Thani | 36° | 24° | 81 mm | extreme | Hot |
| Pattaya | 34° | 26° | 87 mm | extreme | Hot |
| Krabi | 34° | 24° | 131 mm | extreme | Hot |
| Ko Samui | 33° | 25° | 71 mm | extreme | Hot |
| Hat Yai | 34° | 24° | 104 mm | extreme | Hot |
High / low are average daily temperatures (°C). “Feels” reflects how hot or cold it feels, allowing for humidity.
Northern Thailand (Chiang Mai, Chiang Rai, Golden Triangle, Pai)
The first heavy showers usually arrive in mid- to late May, transforming the scrubby hills into green, and Chiang Mai’s air-quality improves as the wet season clears smoke. Trekking becomes more slippery; trails to Doi Inthanon and Huay Tueng Tao are dramatically lusher and waterfalls recommence strong flows. Expect afternoon downpours and cooler evenings under cloud cover, so waterproof shoes and quick-dry layers are handy; fewer international crowds make homestays and small treks more enjoyable.
Northeastern Thailand (Isan: Ubon Ratchathani, Khon Kaen, Udon Thani, Nakhon Ratchasima)
April is the region’s hottest month and the crescendo of Songkran celebrations: Ubon Ratchathani hosts large water fights and traditional ceremonies that are both boisterous and cultural. Heat becomes physically demanding for sightseeing in open archaeological sites, so schedule temple visits at dawn and late afternoon. Expect dust in drier years and pack sunblock and a refillable water bottle for long drives between towns.
Central Plains & Bangkok (Bangkok, Ayutthaya, Kanchanaburi)
April is the hottest month and the country’s high-energy water festival, Songkran, takes over Bangkok with exuberant street splashing and closed roads in some neighborhoods. Temperatures commonly hit the mid-30s°C; plan museum visits in the hottest hours and embrace the festival with quick-dry clothes if joining in. Hotel pools and riverside dining are great escapes, but the city can be crowded with domestic travelers on holiday.
Eastern Seaboard & Gulf Coast (Pattaya, Hua Hin, Koh Chang, Trat coast)
April is hot and humid along the Gulf: Songkran festivities also spread to coastal towns where water fights and temple fairs enliven seaside promenades. Ocean afternoons can be patchy with squalls, so plan island transfers for early mornings. Light, quick-dry clothing and a waterproof daypack help, and boat operators may add extra runs during holiday demand so book ahead for long weekends.
Gulf Islands (Koh Samui, Koh Phangan, Koh Tao)
April is hot and humid and also the period when Songkran energy reaches the islands, especially Koh Phangan where parties and rituals may intensify. Sudden showers are possible and late afternoons can bring isolated thunderstorms; schedule diving in the morning for best visibility. Lightweight clothing and waterproof pouches for phones will keep you comfortable during beach festivities.
Andaman Coast & Phuket Region (Phuket, Krabi, Phi Phi, Khao Lak)
April is hot, humid, and party-oriented as Songkran affects towns and beaches - Phuket’s nightlife heats up while daytime activities can feel draining in peak sun. Storms are still infrequent, but heat and humidity make midday sightseeing uncomfortable. Early-morning boat departures remain advisable, and water-based activities offer a welcome cooldown; carry light clothing and keep hydrated.