Vat Purnima Vrat is similar to Vat Savitri Vrat. Married women observe Vat Purnima Vrat for well-being and long life of their husband.

Most of the festivals in Amanta and Purnimanta lunar calendar fall on the same day. Purnimanta calendar is followed in North Indian states, mainly in Uttar Pradesh, Madhya Pradesh, Bihar, Punjab and Haryana. In rest of the states usually Amanta lunar calendar is followed.

However Vat Savitri Vrat could be considered as an exception. In Purnimanta calendar Vat Savitri Vrat is observed during Jyeshtha Amavasya which coincides with Shani Jayanti. In Amanta calendar Vat Savitri Vrat, which is also called as Vat Purnima Vrat, is observed during Jyeshtha Purnima.

Hence married women in Maharashtra, Gujarat and southern Indian states observe Vat Savitri Vrat 15 days later than that of North Indian women. However the legend behind observing the fast is same in both calendars.

According to legend great Savitri tricked Lord Yama, the lord of death, and compelled Him to return the life of her husband Satyawan. Hence Married women observe Vat Savitri Vrat for well-being and long life of their husband.