Southeast Asia is warm all year, but the rain is not evenly spread. Two monsoon systems bring wet weather at different times to different coasts, so the best month for Bangkok is not the best for Bali. Here is how to match your dates to the right destination.
The general pattern
On the mainland (Thailand, Cambodia, Laos, most of Vietnam), the dry season runs from roughly November to April and the wet season from May to October. November to February is the coolest and least humid stretch. March to May is very hot, with temperatures often above 35°C in Bangkok and Siem Reap.
The wet season is not a washout. Rain usually arrives as heavy afternoon showers, and mornings are often sunny. In exchange you get green landscapes, fewer crowds and lower hotel prices. The exceptions are the peak of the monsoon on some coasts, when seas are rough and boats don’t run, and the typhoon season in Vietnam and the Philippines.
Country by country
Thailand. November to February is the most comfortable time for Bangkok, Chiang Mai and the temples of the north. The Andaman coast (Phuket, Krabi, Koh Lanta) is best from November to April, and boat services and many resorts are reduced from May to October. The Gulf islands (Koh Samui, Koh Phangan, Koh Tao) have a different pattern, with the best weather from about January to August and the heaviest rain in October and November. Chiang Mai has smoky skies from February to April because of agricultural burning, so consider the cooler months for the north.
Cambodia. November to February is ideal for Angkor Wat, with cooler mornings. By April it is very hot. In the wet season, from June to October, the temples are quieter and surrounded by green fields, though some paths flood.
Vietnam. The country is long and its regions have different weather. Hanoi and the north are best in October–November and March–April. Winters from December to February can be cold and gray, and Sapa can be near freezing. The central coast (Hue, Da Nang, Hoi An) is driest from roughly February to August, with typhoons and flooding most likely from September to November. The south, including Ho Chi Minh City and the Mekong Delta, is dry from December to April.
Indonesia. Bali and Lombok are best from about April to October, with May to September the driest and most popular months. Komodo National Park is good for diving and boat trips from April to December. In Bali, July and August and the Christmas period are the busiest and most expensive weeks.
Malaysia. The west coast (Penang, Langkawi) is best from November to March. The east coast and islands (Perhentians, Tioman, Redang) are best from March to October, and many resorts close during the northeast monsoon from November to February.
The Philippines. The dry season runs from about December to May, and typhoons are most likely from July to October. For island hopping in Palawan, February to May offers the calmest seas.
Timing by activity
- Diving and snorkeling: Pick calm, clear periods. Thailand’s Andaman coast is best from January to March, while Komodo is best in the dry season, and Tioman and the Perhentians are best from May to September.
- Trekking: Cooler months are more comfortable. In northern Thailand and Vietnam, aim for November to February, but pack warm clothes for the evenings.
- Festivals: Songkran, the Thai New Year, takes place from April 13–15 and involves city-wide water fights. It is fun, but it is also very hot and crowded, and some shops close. Nyepi, Bali’s Day of Silence, falls in March or April (the date varies). For 24 hours the whole island, including the airport, shuts down. Tet, the Vietnamese lunar new year, falls in January or February, when many businesses close for several days and transport is very busy.
- Photography: The weeks just before and after the rainy season often give the greenest rice fields, clear air and dramatic skies.
Tips for planning
- Check the coast, not the country. If one side of Thailand or Malaysia is rainy, the other is often dry. Choose the beach to match the month.
- Book early for December and January. These are the busiest months. Book flights and hotels three to six months ahead if you plan to travel over the holidays.
- Carry a light rain jacket. A cheap poncho is enough. Quick-drying clothes work better than cotton in humid weather.
- Be flexible in the wet season. Keep a day or two free in your plans so a storm doesn’t disrupt a ferry or flight connection. Build in extra time before any international departure.
The short version
For a first visit, November to February is the safest choice for the mainland, and May to September for Bali and the southern islands. If you can only travel in the wet season, you can still have a good trip: pick the regions with drier conditions, travel in the mornings and enjoy the lower prices.