Broadly speaking, there are two main seasons in Indochina: the rainy season, from May to October or November, and the dry season from December to April. However, it’s a large region with plenty of microclimates, so you’re sure to find pleasant weather somewhere regardless of when you plan to travel.
Towards the end of the dry season, in March, temperatures begin to rise, and in some places can top 40°C in April with high humidity. The highlands offer a refreshing respite at this time.
During the rainy season, there are some key areas which experience disruptions. The Mekong Delta can flood, making travel difficult. In Thailand, the Andaman Coast experiences the worst of the rain – and rough seas can prevent boats from reaching places such as Bamboo Island, near Kep. However, in the Gulf of Thailand at this time, rain is lighter, there are fewer crowds, and some islands – such as
Koh Samet – enjoy a pleasant microclimate. Heavier rains are likely here in September and October though.
Tropical cyclones can also occur in coastal areas during the rainy season; keep an eye on weather reports if traveling there during this time.
To see turtles nesting in Vietnam’s Con Dao Archipelago, head there in July, August or early September.
Tet is Vietnam’s largest festival, to welcome in the New Year. It takes place in late January or early February, on the same day as Chinese New Year. It’s incredibly good fun – but if you don’t plan to join in, you may be best avoiding this period, as there will be huge crowds, public transport will be busy and many attractions will close for up to a week.
Kho Pha Ngan is a sleazy tornado of tourists at any time of year – but once a month – especially in January - it’s even worse, as up to 30,000 hedonists arrive in time for the Full Moon Party. There’s no traditional element to this festival, which was created for and by westerners. Accommodation is fully booked, music blares all night and the beach will be covered in broken glass and burning cigarettes – it’s best avoided, as are the “Half Moon Parties” for those who are passing through later in the lunar cycle.