The best time to visit Bhutan is in the spring, in the months of March, April and May and the autumn, in the months of September, October and November because the weather during these months are more mild. In addition, many of the largest festivals in Bhutan take place during these months. In the autumn, the skies are clear and blue affording views of the high Himalayas from passes and various other vantage points. Autumn is also the time of year when the black-necked cranes migrate to central and eastern Bhutan for the winter. The skies are less clear during the spring but the flowers are in bloom. The downside of traveling during these peak months is that there are more tourists in general and Druk Air reservations need to be confirmed in advance to ensure availability.
The summer months of June, July, August and even early September are typically the monsoon months, so you may encounter rain which may be an obstacle in your journey. The winter months of December, January and February can be cold but the skies are clear and blue. Some treks are closed during these months due to the weather conditions. The upside of traveling during the off-peak months is that reservations are easier to secure, less expensive, and there will be fewer tourists around. But truly, Bhutan is spectacular any time of the year and your trip will be a great adventure no matter when you decide to visit!
Want to know more? Check the current weather condition of Bhutan.