Tithi
A lunar day — the time the Moon takes to gain 12° on the Sun.
A tithi is not a day. It is the interval in which the Moon gains twelve degrees of longitude on the Sun, so it runs anywhere from about 19 to about 26 hours. That is why a tithi can start mid-morning and end the next afternoon, why one can be skipped entirely (kshaya), and why two calendars can honestly name different civil days for the same festival — they are answering 'which day carries this tithi?' with different rules.
What Tithi governs
These recurring vrats are defined by a tithi — they return on the same lunar day of every month, which is why their civil dates move each year.
- Ahoi Ashtami A mothers' vrat, kept for the wellbeing and long life of one's children. The fast runs through the day and is broken in the evening, in many families only after the stars are seen — and in some, after moonrise.
- Amavasya monthly
- Ashtami twice monthly
- Chaturthi monthly
- Dwadashi monthly
- Ekadashi twice each lunar month
- Masik Shivaratri monthly
- Navami monthly
- Pradosh Vrat twice each lunar month
- Purnima monthly
- Sankashti Chaturthi monthly
- Saptami monthly
- Shashti monthly
Find the tithi anniversary of a date →