Adhika Maasam (extra month) is inserted in Vedic Calender (Panchang), to keep the lunar and solar calendars aligned. Position of Adhika Maasam amongst the other months is variable, re-occurring about every 32.5 months.
According to Vasishtha Siddhartha (Treatise of Vasishtha), Adhika Maasam or the extra lunar month occurs after every 32 months, 16 days and 8 ghati. (A ghati is 1⁄60th of a sidereal day, approximately 24 minutes, so 8 ghati is about 3 hours.) Concept of Adhika Maasam is unique to the traditional Vedic lunar calendars.
It is one of the most accurate methods to adjust the gap between Solar and Lunar Year.
Transit of the sun from one rāśi (30 degrees sidereal zodiac) to the next is called sankranti or sankramana.
If a lunar month elapsed without a sankranti and the next transit is into Mesha (Aries), then this month without transit is labelled Adhik Chaitra (because Sun is in Aries and Fullmoon occurs when Moon transits Chitra Nakshatra. So month is named after that nakshatra).
The next month will be labeled according to its transit as usual and will get the epithet nija (original) or shuddha (clean), in this case Nija Chaitra. The terms Pratham (first) Chaitra and Dwitiya (second) Chaitra may also be used.
Adhika māsam (month) is the first of two whereas an adhika tithi is the second of two.
Extra Month, or Adhika Māsa falls every 32.5 months on an average. It is also known as Puruśottama Māsa, it is said that the name was given by Lord Vishnu as his name to this month. The solar year is made up of 365 days and about 6 hours, and the lunar year is made up of 354 days. Thus there is a gap of 11 days, 1 hour, 31 minutes and 12 seconds between the lunar and the solar years. As this gap accumulates each year, it approximates in three years to one month. No adhik mas falls during Margsheersh to Magh. A case of Adhik Karttik is extremely rare, but in the 250-year span (1901-2150 CE) it would occur once, in year 1963 CE.
Scientific Calculation behind Adhika Maasam
Moon, which is the only satellite of earth, takes about 27.3 days to make one complete orbit around the our planet.
Earth orbits around the sun once every 365.2422 days (earth’s orbital speed of 29.79 km per second). The earth and the moon in 27.3 days have moved as a system about 1/12 of the way around the sun. This means that from one full moon to the next full moon, the moon must travel 2.2 extra days before it appears full moon.
This is due to the curve of the earth’s orbit around the sun. The moon is still making one complete orbit (circle) in 27.3 days. But to line up with the earth and sun to become a full moon again it takes 29.531 days which means 354.372 days per lunar year.
This makes a variance of 10.87 days a year between a lunar year and a solar year of 365.2422 days per year.
To compensate this difference, the additional month is added after every 32.5 months on an average.
Just as there is the lunar year with the extra month making 13 total, so there is a lunar year with a reduced month, with only 11 months in the particular lunar year. The lunar year with 11 months is very rare. It occurs once in 140 years or once in 190 years.
Religious and Spiritual Significance of Adhika Maasam
There are no festivals observed during this lunar month. All festivals, muhurtas for auspicious ceremonies like marriage, house warming, initiation of mantras etc will be postponed to Nija Maasam.
Rather this month is treated as special and holy month and people perform the adhik mass vrat. Extra mala japas, pradakshinas, pilgrimages, scriptural reading and parayans.
Few even practice strict celibacy and avoid alcohol, meat, tobacco etc during this month.
This is the best month to do any Puja or Havan. Also, if a person wants to chant any specific mantra, he/she should get initiated by a guru in earlier month itself and continue practice.
Any graha dosh or specific dosh nivaran puja and remedies performed in Adhika Maasam to rectify the horoscope gives a better result to the individual.
Upcoming Adhika Maasam
In 2018-2019 during Jyeshta masam (May-June 2018)
In 2020-2021 during Asweeyuja masam (September-October 2020)
In 2023-2024 during Sravana masam (July-August 2023)
In 2026-2027 during Jyeshta masam (May-June 2026)