The typical advice is to avoid Southeast Asia during the rainy season but cycling during this time can have several benefits.
Cloudier skies mean more comfortable cycling. You’re less likely to get sunburned or develop heatstroke and you won’t need to slather on as much sunscreen. You’ll also find lower prices and empty hotels. It’s easy to walk into even the most popular destinations and pick up a room at a bargain price.
Most of the time the rain doesn’t last all day but just for an hour or two, usually late in the afternoon. There’s little point putting on a rain coat as you’ll only sweat to death in it. Just take shelter or bask in the glorious, cooling drops falling from the sky.
The downside to the rainy season is that it can make the roads messy in Laos and Cambodia. Parts of Thailand often see flooding and you won’t have many pictures with gorgeous blue skies. Some resorts close during the rains and if you like to meet other travellers you could feel a bit lonely at times with the whole bar to yourself.
Activities like diving tend to be out because the water is cloudy and rough. Ferries stop to many Andaman Sea islands. Trekking in the jungle during the wet season means leeches!
Remember that the rainy season varies across Southeast Asia. When it’s wet in the north it can be sunny in the south. Also, although each area has a time of year when the monsoon is expected, like all weather it can be fickle. The rains may come early or late so if you show up near the rainy season, prepare to get wet.
Rainy seasons by country:
Country wide – May to October
Country wide – October to April
Country wide – June to October
Borneo – October to March
East Coast – November to January
Hill Stations – September to December
West Coast – April to May, October to November
Bangkok and the north – June to October
Andaman Sea Coast – May to October
Gulf of Thailand – October to January
North – November to April
South – May to November