March, April & May are among the most popular time to travel as temperatures are pleasant and the valleys are abundant in nature; especially as all the flowers start to bloom. Early April witnesses the Paro Tsechu, one of the most popular festivals in Bhutan. Temperatures increase in May, bringing humidity, as well as clouds over the mountains. The rhododendrons should also still be in bloom; ideal for photographs and nature lovers.
June to August (and sometimes in September) monsoon is monsoon season in Bhutan. However, fewer visitors and lower prices can make it a perfectly viable time to visit. Although shows can occur at night without spoiling day time explorations, conditions are not ideal for trekking. Sightseeing is still possible; just be prepared with a raincoat. Views are best in the mornings following nighttime downpours.
September, October and November are ideal for hiking, seeing festivals (particularly the popular Thimphu Tsechu), and enjoying stunning views and pleasant temperatures. Expect around 25°C in the sun, but there will be cooler temperatures in the evenings and at higher altitudes. Black-necked canes migrate from the Tibetan Plateau to the protected Phobjikha Valley each year. They remain in the region from late October to early February. In Gangtey, a special festival is held every November to celebrate the arrival of the birds.
December, January and February are the coldest months in Bhutan, especially in the mountains, but lower prices and clear skies reward those who brave low temperatures. The valleys are warmer and sunny with clear views of the Himalayas. Due to the low temperatures, visitors are fewer.