2035
Monday, 5 November 2035
In 2035 the tithi runs from 4:59 pm on 5 Nov to 7:38 pm on 6 Nov, so it is running at pradosh, the twilight just after sunset on two days, Monday, 5 November 2035 and Tuesday, 6 November 2035. As in most almanacs, the first is taken.
2036
Friday, 24 October 2036
In 2036 the tithi runs from 1:50 pm on 24 Oct to 3:21 pm on 25 Oct; it is running at pradosh, the twilight just after sunset on Friday, 24 October 2036, so that is the day of Chhath Puja.
How the date is fixed
Chhath Puja falls on the sixth day of the bright half of the lunar month Kartika (Shukla Shashthi). The date is the day on which that tithi is running at pradosh, the twilight just after sunset.
About
Chhath is kept on Kartika Shukla Shashthi, the sixth tithi after the Diwali new moon, in October or November. The four days run Chaturthi (nahay-khay), Panchami (kharna), Shashthi (the evening arghya to the setting Sun) and Saptami (the morning arghya to the rising Sun). The Shashthi evening is the main observance, so the day whose sunset carries Shashthi is chosen and the almanac prints the local sunset and the next sunrise. A smaller Chaitra Chhath is kept in the spring on Chaitra Shukla Shashthi.
How it is observed
A 36-hour fast without water after kharna, and arghya offered standing in water to the setting and then the rising Sun.