Blessed Rainy Day (Dzongkha: ཁྲུས་འབབས་ཀྱི་ཉིནམ།), known as Trhuebab, is an important cultural event observed mainly in the eastern Bhutan. It literally mean the descent (བབ་) of blessed water (ཁྲུས་) on earth. The day celebrates neither the rainy season nor the end of the monsoon.
Bhutan observes Thrue Bab annually, on the autumn equinox.
The most auspicious hour for the ablution is determined by astrologers in the service of the Je Khenpo, the chief abbot of the country. They refer to the Bhutanese lunar calendar (essentially the Tibetan lunar calendar), but the exact method of their calculations have not been disclosed. In 2004, they determined the preferred time to be 4:00 p.m., September 23. Citizens who are unable to bathe at the exact hour instead often rise before dawn for a brisk morning splash.
Variant romanizations of the Dzongkha name of the holiday include Thrue-Bab, Thrie-Bab, and Thri-Bab.
The official dates for recent Blessed Rainy Day celebrations are as follows: