The best seasons to visit Bhutan are during Spring (March, April & May) and Autumn (September, October & November). The major Bhutanese religious festivals are held during these seasons and fine Spring and Autumn weather makes it an ideal time for trekking in Bhutan and for traveling throughout the country enjoying great views of Himalayan mountains peaks.
Nevertheless, it is possible to visit Bhutan throughout the year as Bhutan has 4 seasons in a year and each season has its own charm.
Spring – March, April and May
In spring the temperature is pleasantly mild even up to the alpine regions. The trekking season commences in moderate altitudes. Above 3,000 m spectacular rhododendron forest blooms. It is also the perfect time for a rafting tour. In Paro, one of the largest monastic festivals – Paro Tshechu takes place. Rain comes only in May as the harbinger of the approaching monsoon.
Summer – June, July and August
The summer brings with it the monsoon, but this weather should not deter Bhutan travellers. In the settled areas of the medium ranges of Central and Western Bhutan, pleasant summer temperatures without heat or humidity can be found. Rain falls for short periods daily but is manageable. Treks in high mountain areas, are characterised by mild temperature, verdant green meadows, and pastures of Blue Poppies and Edelweiss. Nomads tending their yaks in the high alpines are a common sight.
Autumn – September, October and November
Autumn is the traditional high season in Bhutan. September and October have the highest number of tshechu’s (monastic festivals). Trekkers particularly enjoy the clear view of the mountains in October and the low rainfall. Rice harvest means a picturesque landscape remarkable terraces and changing colour.
Winter – December, January and February
In winter the South beckons. Dry and pleasant conditions make this the best time of year for bird watching in the jungles, village to village trekking in the lower altitudes or a bicycle trip along quiet mountain roads. The trekking routes in the high mountains are covered in deep snow and are impassable at this time of year. The impressive and endangered Black-necked Crane spends the winter in the high valley of Bumdeling (in Eastern Bhutan) and Phobjika (in Western Bhutan).