What is an Adhika Masam / Masa?Adhika Masam is extra / additional month added once in every 2 or 3 years only in the Hindu Lunar calendar so as to synchronize it with the solar calendar. A Hindu lunar year with Adhika Masam will have 13 months instead of the usual 12 months.
The states of Andhra Pradesh, Telangana, Karnataka, Maharashtra and Gujarat follow lunar calendar whereas the states that follow Hindu Solar Calendar don't have Adhika Masam.
Adhika Masam is known by different names in different regions. Different names of Adhika masam are: Purushottam Maas, Mala Maas, Kala Mahina, Adhik Mahina. The word 'adhika / adhik' literally means 'more'.
Why there is Adhika Masam in the Lunar Calendar?Hindu lunar calendar is based on the revolution of moon around the sun while the solar calendar is based on the sun's transition from one zodiac sign / raasi to another. When moon completes one revolution, a new month begins in the lunar calendar.
In most of the north Indian states each month begins on the next day after the full moon day / purnima. For the states of Andhra Pradesh, Telangana, Karnataka, Maharashtra and Gujarat, each month begins the next day after amavasya / new or no moon day.
As moon takes around 29.5 earth days to complete on revolution, there are 354 days in a year in the Lunar calendar. Hence the lunar calendar does not synchronize with the universally accepted / followed Gregorian calendar which has 365 days a year except the leap year. Whereas a month in the Solar calendar has 30 or 31 days and 365 days a year and coincides with the Gregorian calendar.
A month in the lunar calendar starts earlier than the corresponding month in the solar calendar. Hence there is a shortage of 11 days in an year in the lunar calendar than an year in the solar calendar. So to synchronize the lunar year with the Solar / Gregorian calendar, the shortage of 11 days in a lunar year is added up / compensated once in every 2 or 3 years with an extra month consisting of 28 or 29 days. And this extra month is known as Adhika Masam.
But as per solar calendar, once a month Sun transits from one zodiac sign / raasi to another. This transition period is known as Sankramanam or Surya Sankranti. Accordingly there will be 12 Surya Sankrantis as there are 12 zodiac signs / raasis.
In a lunar calendar the particular month that does not have Surya Sankranti is considered as Adhika Masam.
Also Read: Sankranti
Normally no festivals are celebrated in Adhika Masam but these are celebrated in the nija (means actual / real) masam. This extra month is not inauspicious but is added once in every 2 or 3 years for synchronizing and easy calculations. Different regions of the country follow different cultures and traditions in their own way which enriches our cultural heritage. This year (2023) there is Adhika Sravanam which is from 18th July 2023 to 16th August 2023. And Nija Sravanam begins from 17th Aug 2023 for the states where a new month starts after Amavasya / no or new moon day.
Also Read: Importance of Sravana Masam
Years when next Adhika masam falls2023 - Ahika Sravanam
2026 - Adhika Jyestham
2029 - Adhika Chaitram
2031 - Adhika Bhadrapadam
2034 - Adhika Aashadam
2037 - Adhika Jyestam
2039 - Adhika Aswayujam
2042 - Adhika Sravanam
2045 - Adhika Jyestham
2048 - Adhika Chaitram
2050 - Adhika Bhadrapadam
2053 - Adhika Aashadam
2056 - Adhika Vaisakham
2058 - Adhika Aswayujam
2061 - Adhika Sravanam
2064 - Adhika Jyestham
2067 - Adhika Chaitram
2069 - Adhika Sravanam
Reference (courtesy) for the above years and akdhika masam - Hindupad.com