What Is a Tithi (तिथि)?
A Tithi is a lunar day in the traditional Indian calendar. It is measured through the Sun-Moon angular relationship, so it can begin or end at any clock time rather than at midnight.
Tithi and Paksha
The traditional lunar month is commonly described through two halves: Shukla Paksha, the waxing half toward Purnima, and Krishna Paksha, the waning half toward Amavasya. A Tithi is numbered within that half, such as Shukla Navami or Krishna Ashtami.
Why festival dates can differ
Observers may use sunrise rules, local time, regional calendars or a particular sampradaya's convention. A festival date is therefore not simply a fixed Gregorian date. Moonrise and local sunrise can matter for the observance.
How IndiaTime should display it
A useful display should name the location and convention, show the Tithi boundary when verified, and explain whether the listed festival date is fixed, cross-checked, tentative or awaiting verification. It should never disguise an approximate moon phase as a Panchang Tithi.
Open the Hindu calendar guide · Understand months and Samvat · Compare moon phases and Tithi