Trayodashi त्रयोदशी

Trayodashi belongs to the Jaya group — victorious — tithis of contest and conquest. Court cases, competitions, examinations, negotiations, anything adversarial.

Traditionally avoided: Gentle or conciliatory work; peace-making.

The group affinity is strongest on Tuesday, when the weekday and the tithi reinforce one another.

A tithi is the time the Moon needs to gain twelve degrees of elongation on the Sun. Because both bodies move at varying speeds, a tithi runs anywhere from about nineteen to about twenty-six hours — so it seldom matches a calendar day, and it can begin and end at any hour.

The tithi “of the day” is by convention the one in force at sunrise. A tithi that both begins and ends between two sunrises never rules a day at all (kshaya tithi), and one that spans two sunrises rules both (adhika tithi). This is why our panchang shows you the transition time rather than a single name.