For example;
Indonesia - May-October is more dry, less rain
Thailand - November - Feb is more dry, less rain
In general, I like to visit right between rainy season and dry season. This is called "shoulder season". The benefits:
- More green landscapes
- Less people = cheaper prices
- Not too hot or too rainy
- I love the occasional tropical thunderstorm.
Best time to Visit
Cambodia - Angkor Wat in Siem Reap for 4 days. Afterwards, travel to the souther islands for 6-10 days
Thailand - A good 1-month: Bangkok - Chiang Mai - Pai - Chiang Mai - Krabi / Railay Beach - Koh Samui - Koh Phangan - Koh Tao
Malaysia - Go on a food expedition in Penang or Kuala Lumpur for 5 days
Indonesia - Spend the rest of your time, about 3 weeks, traveling around Bali, the Gili Islands or Raja Ampat
Alternative: Swap Indonesia for the Philippines