Varshitap traditionally starts on Chaitra Shukla 8 (Chaitra Shukla Ashtami) every year.

• This is the 8th day of the bright fortnight of Chaitra in the Jain lunar calendar.
• From this day, the year‑long alternate‑day fasting begins.
• The parna (breaking of the varshitap) is done on Vaishakh Shukla 3 (Akshay Tritiya), in remembrance of Bhagwan Rishabhdev ending his long fast with ikshu‑ras (sugarcane juice).

Exact English (Gregorian) calendar dates change every year, so they should be confirmed from the panchang / Jain calendar of your sangh and as per guidance of your guru.

You can read more about the start of Varshitap here