NANAK SHAHI CALENDAR

On the 300th year of Khalsa Panth, The Shromani Gurdwara Parbandhak Committee released the New NanakShahi Calendar (Prepared by S. Pal Singh Purewal) and decided to celebrate the Gurpurbs according to that. NanakShahi calendar has all the basic features of a modern and independent Sikh calendar. The first month is Chet as mentioned in Gurbani and all other months are according to climate. The months are:

Chet = 31 days, Vaisakh = 31 days, Jeth = 31 days,
Haarh = 31 days, Saavan = 31 days, Bhaadon = 30 days,
Assu = 30 days, Kattak = 30 days, Maggar = 30 days,
Poh = 30 days, Maagh = 30 days, Phagun = 30 days.

In leap year the month of Phagun will be of 31 days (February is of 29 days). In this calendar, leap year will have the day added in the last month i.e. Phagun and not in between month i.e. February. The beginning of every month of NanakShahi Calendar will correspond to Christian era calendar as follows:

1 Chet = 14 March 1 Vaisakh = 14 April 1 Jeth = 15 May
1 Haarh = 15 June 1 Saavan = 16 July 1 Bhaadon = 16 August
1 Assu = 15 September 1 Kattak = 15 October 1 Maggar = 14 November
1 Poh = 14 December 1 Maagh = 13 January 1 Phagun = 12 February

In case of leap year, some of the dates will differ from Christian era calendar by one day, from 1st March to 13th March. All the dates mentioned in the NanakShahi calendar will be the true dates as per this system. None of these dates will change every year. Hence, the dates of Gurpurbs will remain same for all the years. Also there will be no question of same event happening twice a year.
Both NanakShahi calendar and Christian era calendar are based on Solar Year. Christian era calendar has days of months as:

January = 31 days February=28/29 days March = 31 days
April = 30 days May = 31 days June = 30 days
July = 31 days August = 31 days September= 30 days
October = 31 days November = 30 days December = 31 days

The number of days selected for the months are not in any systematic order in the Christian era calendar. The month of February that varies in the leap year, is also the second month and not the first or last month of the year. These deficiencies were improved in the NanakShahi calendar. The first five months are of 31 days and last 7 months are of 30 days. The additional day in the leap year is added in the last month of the year (Phagun) and not in between. Hence, NanakShahi calendar is a modern and improvised form of Christian era calendar.