The start timing of Paryushan varies each year and also depends on the Jain sect:

For Shwetambar Jains: Paryushan Parva typically lasts 8 days and begins on the 12th day of the waning moon (Bhadrapada month, according to the Hindu lunar calendar—usually falling in August or September). The exact date varies each year based on the lunar calendar.

For Digambar Jains: Paryushan, called Das Lakshan Parva, lasts 10 days and usually starts one day after the Shwetambar Paryushan begins.

Start Timing: The observances and rituals usually commence at sunrise on the first day of Paryushan. Temples may have special morning prayers and discourses after the sun rises.

For the exact start date and time for a particular year, it is best to consult a Jain Panchang (calendar) or your local Jain temple, as it varies annually according to the lunar calendar.