Bhutan experiences four seasons; autumn (late September to November) is the most favorable to travelers. The skies are clear around this season, so expect to have a full view of the mountains.
Winter occurs from December to February. It is characterized by cool sunny days and cold nights. Daytime temperature can be about 16 to 18 °C (60.8 to 64.4 °F), while night temperature can drop below freezing point. Regions in higher altitudes are covered with snow come wintertime.
Rainy spring sets in by March. Daytime temperature in higher valleys usually reads 20 °C (68 °F). Spring lasts until May.
Bhutan experiences summer in June. It has an average daytime temperature of 27 to 29 °C (80.6 to 84.2 °F) and brings monsoon rain. Floods are common during this season.
You may wish to time your travel around any of the lively tshechus – religious festivals – of the country. Held in temples or villages, tshechus feature bright costumes and masked by the dancers.
The most popular tshechus are the Thimphu Tshechu and the Paro Tshechu. The Thimphu Tshechu is held in the capital Thimphu beginning on the tenth day of the eighth month of the lunar calendar. Paro Tshechu is celebrated in the district of Paro every spring.
Festival dates are based on the lunar calendar, so they change every year. It pays to check the festival schedule before planning a visit.