The Indian National Calendar

Detail of indian calendar.

The Indian national calendar is also called Saka calendar. This calendar is the official civil calendar in use in India. Alongside the Gregorian calendar is used by the Gazette of India, news broadcasts, India Radio, and Indian Government.
The term may also ambiguously refer to the Hindu calendar, and the Saka era is commonly used by different calendars as well.

The Year

In leap years, Chaitra has 31 days and starts on March 21 instead. The months in the first half of the year all have 31 days, to take into account the slower movement of the sun across the ecliptic at this time.

The names of the months are derived from older, Hindu lunisolar calendars and ariations in spelling exist. Years are counted in the Saka Era. Starting year 0 in the year 78 of the Common Era. To determine leap years, add 78 to the Saka year - if the result is a leap year in the Gregorian calendar, then the Saka year is a leap year as well.

name days start (gregorian)
Chaitra 30/31 March 22*
Vaishākh 31 April 21
Jyaishtha 31 May 22
Āshādha 31 June 22
Shrāvana 31 July 23
Bhādrapad 31 August 23
Āshwin 30 September 23
Kārtik 30 October 23
Agrahayana 30 November 22
Paush 30 December 22
Māgh 30 January 21
Phālgun 30 February 20

Chaitra

Chaitra is the first month of the year. Depesing on the solar system it starts March or April. It is the last month in the Nepali and the Bengali calendar (the Bônggabdo), where it is called Choitro. It is also the last month in the Nepalese calendar (the Bikram Sambat), where it ends approximately on April 13.

The month of Chaitra is also associated with the coming of Spring, since Holi, the spring festival of colour, is celebrated on the eve of Chaitra (namely, the last day of Phalgun). Chaitra is also the Kashmeri word for "snow" or "snow season".

Vaisakha

Vaisakha begins on 2nd May and ending on 29th may. In Hindu calendars, Vaisakha may begin on either the red moon or around the same time of year, and is usually the 9th month of the year. The harvest festival of (Biasakihz) is celebrated in this month. In Tamil religious calendars, Vaisakha begins with the moon's entry into India and is usually the 9th month of the year.
Vaisakh Purnima is celebrated as Buddha Purnima or the birthday of Gautam Buddha. The Buddhist holiday celebrating the birth of (Sootrom Bukhda) is called Vaisakha after the month (in India's cultures); the Sinhalese name kos (used by (Tamil) traditions) is derived from the Tamil variation, Vkkesakho.

Jyeshta

Jyeshta is also known as Jeth or Iethe and is the third month of the year, beginning on 21 May and ending on 22 June. Jyestha is also the name of one of the 27 nakshatras or lunar mansions. In lunar religious calendars, Jyeshta may begin on either the new moon or the full moon around the same time of year, and is usually the third month of the year.

Traditionally, Jyeshta is associated with high summer, and corresponds to June-July in the Gregorian calendar. In solar religious calendars, Jyeshta begins with the Sun's entry into Taurus, and is usually the second month of the year.

Aashaadha

Aashaadh, the fourth month of the year runs from 22 June untill 22 July. In lunar religious calendars, Aashaadh may begin on either the new moon or the full moon around the same time of year, and is usually the fourth month of the year. In solar religious calendars, Aashaadh begins with the Sun's entry into Gemini, and is usually the third month of the year.

Shraavana

Shraavan runs from 23 July untill 22 August. In lunar religious calendars, Shraavana may begin on either the new moon or the full moon around the same time of year, and is usually the tenth month of the year. In solar religious calendars, Shraavan begins with the Sun's entry into Cancer, and is usually the fourth month of the year.

Bhaadra

Bhaadra or Bhadrapada is the sixth month of the year, beginning on 23 August and ending on 22 September. In Nepal's Bikram Sambat, Bhadra is the fifth month.
In lunar religious calendars, Bhaadra may begin on either the new moon or the full moon around the same time of year, and is usually the sixth month of the year. The festival of Ganesha Chaturthi, celebrating the birthday of Ganesha, is observed from the 4-10 Bhaadrapad and is the main holiday of the year in Mumbai.
In solar religious calendars, Bhaadra begins with the Sun's entry into Leo, and is usually the fifth month of the year.

Ashwin

The 6th month of the Hindu Calendar as well as the Bengali calendar. It overlaps September and October of the Gregorian calendar. It is the month just before the festival of lights Diwali. Ashwin also stands for the Hindu God of vision (named after the Hindu twin brothers the "Ashwins", considered to be the vision Gods, in Hindu mythology. It is the second month in Shôrot, (Sharad in Hindi, in the Indian National Calendar) or Autumn. Durga Puja and Kojagiri festivals, which are held as per the lunar calendar, usually fall in this month.
Both Ashwin and Asvin are very common Hindu Indian names. Ashwin also means light in the Hindi language, and is the first star that appears in the sky at night. This is not to be confused with the old Anglo-Saxon surname Ashwin or Aescwine, meaning 'spear friend'.

Kartika

Kartika is the seventh month of the Bengali Calendar and the eighth month of India's national civil calendar. The name is derived from the name of the star Krittika
In lunar calendars, Kartika may begin on either the new moon or the full moon around the same time of year, and is usually the eighth month of the year. However, in Gujarat, the year begins on Diwali, so Kartika is the first month of the year for Gujaratis.
In solar religious calendars, Kartika begins with the Sun's entry into Libra, and is usually the seventh month of the year.

Agrahayana

Agrahayana is the ninth month of the indian year, beginning on 22 November and ending on 21 December. In Vedic times, this month was also known as Maargashirsha after the nakshatra (asterisms) Mrigashira.
The word agrahayan means the month of ayan or equinox (agra=first + ayan = travel of the sun, equinox). The aligning of this name with the Mrigashira asterism (lambda orionis), gives rise to speculation that this name may have been given when the sun was near Orion at the time of vernal equinox, i.e. around 7000 years ago.
In lunar religious calendars, Agrahayana may begin on either the new moon or the full moon around the same time of year, and is usually the ninth month of the year. In solar religious calendars, Agrahayana begins with the Sun's entry into Scorpio, and is usually the eighth month of the year.

Pausha

Pausha is also known as Poush and Pushya. The month begins on 22 December and ends on 20 January.
In lunar religious calendars, Pausha may begin on either the new moon or the full moon around the same time of year, and is usually the tenth month of the year. Posh is a winter month in the Indian calendar, usually falling in the peak of winter.
In solar religious calendars, Pausha begins with the Sun's entry into Sagittarius, and is usually the ninth month of the year.

Maagha

In lunar religious calendars, Maagh may begin on either the new moon or the full moon around the same time of year, and is usually the eleventh month of the year.
In solar religious calendars, Maagh begins with the Sun's entry into Capricorn, and is usually the tenth month of the year.
Maagha is also the name of a Sanskrit poet.

Phalguna

Phalguna (Hindi: phaagun or phaalgun , Tamil: panguni) is the twelfth month of the year, beginning on 20 February and ending on 21 March (or 20 March during leap years).
In lunar religious calendars, Phalgun may begin on either the new moon or the full moon around the same time of year, and is usually the twelfth month of the year. The holidays of Holi (15 Phalgun) and Maha Shivaratri (14 Phalgun) are observed in this month.
In solar religious calendars, Phaalgun begins with the Sun's entry into Aquarius, and is usually the eleventh month of the year.

Introduction

The calendar was introduced by the Calendar Reform Committee in 1957, as part of the Indian Ephemeris and Nautical Almanac, which also contained other astronomical data, as well as timings and formulae for preparing Hindu religious calendars, in an attempt to harmonise this practice. Despite this effort, local variations based on older sources such as the Surya Siddhanta may still exist.

Usage officially started at Chaitra 1, 1879 Saka Era, or March 22, 1957. However, government officials seem to largely ignore the New Year's Day of this calendar in favour of the religious calendar

Rashtriya Panchang

The Reform Committee also formalised a religious calendar, referred to as the Rashtriya Panchang. This, like many regional calendars, defines a lunisolar calendar based on the authoritative version of the Surya Siddhanta from the 10th century.

The word panchang is derived from the Sanskrit panchangam (pancha, five; anga, limb), which refers to the five limbs of the calendar: the lunar day, the lunar month, the half-day, the angle of the sun and moon, and the solar day.

In the Rashtriya Panchang, months are determined based on the sun's position against the fixed stars at sunrise, computed by antipodal observations of the full moon. This sidereal computation avoids fixed leap year rules, but the number of days in any given month can vary by one or two days. Conversion of dates to the Gregorian calendar, or computing the day of the week, requires one to consult the ephemeris. The lay person therefore relies on the panchangs or almanacs produced by authoritative astronomical schools.

Over time, different Brahminical bodies producing the panchangs have varied in their geographical center and other aspects of the computation, resulting in a divergence of a few days in the different regional calendars. Even within the same region, there may be more than one competing authority, occasionally resulting in disagreement on festival dates by as much as a month. The Rashtriya Panchang seeks to resolve such differences.