The reason being that there is direct flight from these countries and also because it takes about two days to travel to Bhutan from the continents of America or Europe.
If you Google ‘when is the best time to visit Bhutan’, you will conclude that Spring and Autumn is the best time to visit Bhutan. It is true that Spring and Autumn has pleasant weather with clear blue sky but it would be wrong to conclude that Spring and Autumn is the best time to visit Bhutan. Winter and Summer has its charm and for some people winter and spring may be a better time to visit Bhutan.
Spring and Autumn has good weather, warm and sunny days, and therefore is the best time to travel and experience Bhutan. Spring is March, April and May and Autumn is September, October and November.
Early spring and late autumn will be chilly in the evenings but compared to Winter, it will be far more pleasant. You can expect clear blue sky on most days in Spring and Autumn. Autumn will be colorful with the rice fields gold in color, ready and ripe for harvest. Since most cultural festival take place in open grounds and in courtyards of the Dzongs, absence of rain and cold is a desired weather to conduct a festival. Spring and Autumn is a good time to catch a cultural festival in Bhutan. Do expect some rain in Autumn and late Spring.
December, January and February are considered as Winter months. Winter in Bhutan is cold but it only gets cold after sundown. Day time is warm under the winter sun and the clear blue sky is a common occurrence, unless it is snowing. Average day temperature will be about 10-20 degree celsius in places like Thimphu and Paro. Punakha and Wangdue is much warmer than Thimphu and Paro. Night temperature may drop a few degrees below zero.
June, July and August are Summer months and the disadvantages of visiting Bhutan in Summer is that the weather will be cloudy with big chances of rainfall. Summer in Bhutan is considered as the monsoon season but it does not rain continuously for days, nor does it rain heavily in the northern part of Bhutan which is popular with tourist. Trekking is not recommended in winter and summer.
Disadvantages of visiting Bhutan in Spring and Autumn?
Advantages of visiting Bhutan in Winter and Summer?