What is Adhika masa? When Adhik month or extra lunar month comes in Hindu Astrology? Here is a good article about Adhika masa published in Bangalore Mirror. The article briefly discusses the time of Adhika masa and pujas and rituals to be performed during Adhika masa.
Mr Niranjan Babu wrote for Bangaloremirror.com
A lunar year has 354 days while a solar year has 365 days. This means, at the rate of 11 days a year, in the course of 2 years 8 months, the difference is 29 and a half days equal to a lunar month. Therefore every 33rd month is considered an ‘Adhika Masa. In practice, the speeds of the Sun and Moon can cause the Adhika Masa to be between the 28th and 36th months. ‘Adhika Masa (also called ‘Mala masa and ‘Purshotthama masa) is not followed in Assam, Bengal, Kerala, Orissa and Tamil Nadu since they follow the 365 day calendar.
The story runs that ‘Adhika Masa goes to Lord Vishnu and laments that all “demigods and human beings have rejected this month for any auspicious function”. Vishnu (in the form of Krishna) blesses the month that it will become equally potent and divine as Him.
It is said those that worship Adhika Masa with faith and devotion will be able to burn all sins of past births. Donation with sincerity and love during this month is said to come back manifold to give one peace, prosperity and plenty. You can donate to old age homes, homes for physically or mentally challenged people or juvenile homes.