Bhutan's festivals can be divided into traditional festivals, non-religious festivals and religious festivals. Most of the festivals are celebrated according to Bhutanese calendar. Among them, the most important one is Tshechu, an annual religious Bhutanese festival held in each district or dzongkhag of Bhutan on the tenth day of a month of the lunar Tibetan calendar. The month depends on the place. Tshechus are religious festivals of the Drukpa Lineage of the Kagyu school of Tibetan Buddhism.
Tshechus are large social gatherings, which perform the function of social bonding among people of remote and spread-out villages. Large markets also congregate at the fair locations, leading to brisk commerce. The Thimphu tshechu and tha Paro tshechu are among the biggest of the tshechus in terms of participation and audience.
During the festivals, tourists are not allowed to smoke. And you’d better behave more politely, no loudly talking or photographing.
The Bhutanese calendar is a variant form of the main Tibetan calendars. It is very much like the Phugpa system, but has different values for some of the main variables – for example, the mean longitude of the Sun at any time. The mean motions of the Sun, Moon and planets are exactly the same as those used in the Phugpa and Tsurphu systems. However, the Bhutanese calendar has one very curious and unique feature – the weekdays are one ahead, not only of the main Tibetan calendars, but the western calendar as well.