When to go to Bhutan
The southern part of Bhutan is tropical, and in general the eastern region of the country is warmer than the central valleys. However, the higher the altitude, the cooler the weather, and with a brisk wind blowing down off the mountains even low-lying valleys can become chilly.
The best time to visit Bhutan is from October to May when the climate is mainly dry and sunny, while in December and January snow may block mountain passes and travel is therefore restricted to the western valleys.