When's the Best Time to Visit Southeast Asia?

Although relatively compact, Southeast Asia has a seemingly infinite amount of climates to match its varied mountains, beaches, religions and cuisines. Weather patterns vary wildly even within the same country -- in Thailand, for instance, when it’s the sunny dry season in Phuket, it’s time for monsoons just 300km away on the island of Koh Samui.

Whether planning a weeklong beach holiday or a three-month trek around the region, it’s useful to know what weather to expect. Here’s a handy guide to high and low seasons in some of Southeast Asia’s most popular spots.

Bali, Indonesia
When to go: April to October. Temperatures average 24-30°C and the weather is mostly dry. July to September is peak holiday season and when you can expect to pay the highest rates. 

Rainy season: December to February. These months average 309mm of rain, although it’s more akin to short, intense showers than day-long deluges, meaning you can still enjoy an excellent (and cheap) holiday.

Malaysia
When to go: January to March and June to September. Malaysia straddles the equator, so it’s hot and humid year-round but these months have the lowest average rainfall.

Rainy season: October to December, though monsoons continue through to February in Borneo.

Singapore
When to go: January to October. Like Malaysia, tiny Singapore’s weather stays fairly constant throughout the year, with temperatures only ranging from 30-33°C. June to August is driest, although flash thunderstorms and stifling humidity are never out of the question.

Rainy season: November to December average 250mm of rain each per month.

Thailand
As one of the larger countries in the region, and given its proximity to both the Gulf of Thailand and the Andaman Sea, Thailand sees a variety of different weather patterns throughout the year. The good news is that because Koh Samui and Phuket have opposite rainy seasons, a world class beach is never too far away.

• Bangkok
  When to go: November to January is the "cool season", meaning average temperatures drop into the mid-20s. February to May is relatively dry, but humidity is on the rise
  
  Rainy season: June to October

• Chiang Mai
  When to go: November to February. Thais prefer escaping to the country’s second-largest city due to its proximity to mountains and cooler temperatures. In the evening temperatures can get as low as 15°C, but hover around a sunny 30 degrees in the daytime. Temperatures rise to between 25 and 40 in March and April
  
  Rainy season: May to October

• Koh Samui
  When to go: April to September and January to March
  
  Rainy seasons: October to December. And it rains A LOT

• Phuket
  When to go: November to February is known as the “cool” season, meaning temperatures hover around 30 during the day and dip to a comfortable 23-25 at night. March to May is very hot, which isn’t such a bad thing when the beach is nearby
  
  Rainy season: Monsoon season is May to October although, like Bali, showers are generally on the brief and intense side, meaning you’re apt to find plenty of great deals (and value) at resorts

Vietnam
Like Thailand, Vietnam has three distinct climates. Hanoi gets downright chilly during the winter months, Ho Chi Minh City sees monsoons and temperatures remain fairly pleasant in central Vietnam throughout the year.  

• Central Vietnam/beaches (including Da Nang, Hoi An, Hue and Nha Trang)
  When to go: January to May. This is the driest time of year and temperatures average 21-30°C. June to August is also fairly dry, but gets increasingly hot and humid.
  
  Rainy season: June to July and September to November in Da Nang. October to early December in Hue, Hoi An and Nha Trang

• Hanoi
  When to go: March to April (spring) or October to December (autumn) offer the mildest temperatures, ranging from 18-25°C. In winter (January to February) daytime temperatures can get down to 12°C, although the season is also fairly dry
  Rainy season: May to September. Temperatures also climb up to 40°C during these summer months

• Ho Chi Minh City
  When to go: March to May is the hot, dry season, with a daily average temperature of 32°C. December to February is a bit cooler, averaging 20-30°C throughout the day
  
  Rainy Season: Late May to early November

Sources: Fodors.com, Frommers.com, Concierge.com, Vietnam Embassy, Wikitravel, Weather.com.  

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Kate McFarlane is based in Sydney, Australia