September - November (Spring) March-May (Spring) is the best time to visit Thimphu.
This is the time when the skies are clear, the Weather in Thimphu is pleasant and feasible to travel. This is also a great time for adventure activities and trekking. Paro Tsechu
is also celebrated during the spring season and it is one of the best times to be in Bhutan. The end of November could turn out to be cold so don't forget to pack woollens. During the months of summer, the weather turns out to be extremely wet as well as humid and hence there are high chances of rain. During the months of winter, it is excessive cold as well as dry weather.