This year (2026), Varshitap starts on:

11 March 2026 (Wednesday) Tithi: Chaitra / Phalgun Krishna Ashtami

Many will take Varshitap saṅkalp (vow) on this date, and then continue alternate-day fasting until Akshay Tritiya next year.

You can also see the Varshitap 2026 discussion here