Because of its geographical vastness, it’s better to look at Asia on a monthly calendar, and use that to determine which destinations will work for your schedule:
January & February (Southeast Asia)
If you have your heart set on Cambodia, this is the best month to visit. Temperatures hover somewhere around 25°C, there is very little rain if any, and skies are blue. If Laos is on your bucketlist, the end of January and into the whole month of February, the weather is fantastic this time of year.
March & April (Sri Lanka)
There’s whale watching, and then there’s Blue Whale watching – If you want a chance to see these gentle giants in the wild, Sri Lanka is the best place to do this and March is the best time of year. The end of March & early April marks the end of Southeast Asia’s dry season, and while the weather can still be fabulous, temperatures can climb to 40°C with humidity that can make travel uncomfortable.
April & May (China)
China can feel unbearably humid during the summer months, but the spring brings lighter domestic crowds, moderate pricing and less line-ups for major tourist sites. September and October are also excellent months for visiting China, especially the larger cities like Hong Kong, Beijing and Shanghai.
July & August (Indonesia)
If you have designs on visiting Indonesia, especially Bali, you couldn’t dream up better weather. Temperatures are comfortable, winds constant and skies crystal clear. Unfortunately, Bali becomes crammed with Australian and European tourists and it can make pricing quite high. Sumatra, Java and Sulawesi are less crowded (and less traveled), so consider spending most of your time exploring off-the-beaten path locales.
September & October (China)
While these are fantastic months to visit China, during ‘Golden Week’ (29th September to 10th October), the entire country is on holiday. Trust me, you don’t want to attempt a holiday when 1.4 billion people are on the roads, in the skies and on board every train in the country, all at once!
December – March (India)
This window of time is India’s high season – In the southern part of the region, the days are pleasant and warm, and the nights are cool. In December and January, the northern parts of the region see warm days, and chilly nights, with temperatures climbing steadily from February onwards. For those wanting to explore the Himalayan region, mountain passes to Ladakh and higher elevations open from July and remain accessible into September, a time when the monsoon rains arrive. Southern regions like Kerala see heavy rains from October into early December.
April – June is the low season for much of India – May and June are swelteringly hot, and the June monsoon rains bringing stifling humidity. It may the best time of year to travel if you’re on the strictest of budgets, but not always the most comfortable if you’re moving around.