Al Hijra and the Islamic calendar

Al Hijra is the first day of the Islamic New Year and of the Islamic month of Muharram. It marks the day when Mohammed began his migration (Hijra, هِجْرَة) from Mecca to Medina in Islamic Year 1 (1 AH), 622 CE. Ras al-Sana (رأس السنة ) is the Islamic celebration of the new Hijri year.

Dates of Al Hijra in western calendar, 2010–13

2010 (1432 AH): 7 December
2011 (1433 AH): 26 November
2012 (1434 AH): 15 November
2013 (1435 AH): 5 November

NB future dates are estimates and depend on first sightings of the crescent moon.

The Islamic (Hijri) calendar

Watercolour painting of the crescent MoonCrescent moon. © Watercolour by Sally Russell The Islamic calendar is the classic lunar calendar consisting of 12 synodic (lunar) months, each of 29.5 days, giving a year of 354 days. It is 11.25 days shorter than the tropical year.

Each month starts with the first naked eye sighting of the crescent Moon (Hilal). Since this depends on a variety of factors printed calendars are based on estimates of the sighting. Calculations which estimate when the crescent Moon will be visible by taking into account the astronomic factors which determine its visibility ensure the precision of these calendars.

Since it is not possible to have half days, a year of 354 days is achieved by having odd months of 30 days and even ones of 29 days, giving an average month of 29.5 days. Because the synodic month (the period between successive new moons) is actually slightly longer than 29.5 days, in leap years an extra day is added to the 12th month (Zul Hijja). Leap years in the lunar calendar are those in which dividing the year number by 30 gives remainder 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 or 29. This gives a calendar with average month length 29.53056 days, quite close to the synodic month.

The years are numbered with Islamic Year 1 corresponding to 622 CE. Islamic New Year 1428 starts on 20 January 2007 in the Gregorian calendar.

Not all Islamic countries use the first sighting of the crescent Moon to signal the start of the month. In Saudi Arabia and Egypt the beginning of the month is fixed by the relative timing of sunset and moonset on the 29th day of each month. If the Moon sets before the Sun the next day is the 30th of the month. If the Sun sets before the Moon (by at least 10 minutes in Egypt) the next day is the first of the next month.

Months of the Islamic calendar

Month Days Month Days
1. Muharram 30 7. Rajab 30
2. Safar 29 8. Sha’ban 29
3. Rabi Al-Awwal 30 9. Ramadan 30
4. Rabi Al-Thani 29 10. Shawwal 29
5. Jumada Al-Ula 30 11. Zul Qida 30
6. Jumada Al-Thani 29 12. Zul Hijja 29*
* Zul Hijja has 30 days in a leap year.

Calendars from around the world

The information above is an excerpt from the Museum's e-book 'Calendars from around the world', written by Alan Longstaff.

All human societies have developed ways to determine the length of the year. These systems – calendars – also dictated when the year should begin, and how to divide the year into manageable units of time, such as months, weeks and days.