2016
Tuesday, 1 November 2016
In 2016 the tithi runs from 1:39 am on 1 Nov to 4:11 am on 2 Nov. It covers the whole aparahna (1:10 pm–3:23 pm) on Tuesday, 1 November 2016, so that is the day of Bhai Dooj.
2017
Saturday, 21 October 2017
In 2017 the tithi runs from 1:37 am on 21 Oct to 3:00 am on 22 Oct. It covers the whole aparahna (1:13 pm–3:29 pm) on Saturday, 21 October 2017, so that is the day of Bhai Dooj.
How the date is fixed
Bhai Dooj falls on the second day of the bright half of the lunar month Kartika (Shukla Dwitiya). The date is the day whose aparahna, the early afternoon (the fourth of five equal parts of the daytime) the tithi covers completely. If it covers only part of it on two days, the day on which it covers more of that period is taken†.
† Practice varies between schools; our faculty is reviewing these rules.
About
Bhai Dooj falls on the second tithi of the bright half of Kartika, the second tithi after the Diwali new moon, in October or November. It is Yama Dwitiya, the day Yama is said to have visited his sister Yamuna, and the aparahna (the fourth of five parts of the day, the early afternoon) is the governing period, so the day whose aparahna Dwitiya covers is chosen. Bhai Dooj therefore comes two or three days after Diwali, and in some years on the same day as Govardhan Puja, which takes the Pratipada of the morning. Sisters mark their brothers' foreheads and feed them; in Bengal it is Bhai Phonta, in Nepal Bhai Tika, and in Maharashtra Bhau Beej. The Kayastha community keeps Chitragupta Puja on the same day.
How it is observed
Sisters apply tilak to their brothers in the afternoon and share a meal; a bath in the Yamuna is traditional at Mathura.