The Islamic calendar: the 12 Hijri months and the sacred months

The twelve months of the Hijri calendar are, in order: Muharram, Safar, Rabi al-Awwal, Rabi al-Thani, Jumada al-Awwal, Jumada al-Thani, Rajab, Sha'ban, Ramadan, Shawwal, Dhul-Qi'dah and Dhul-Hijjah. Each month begins with the sighting of the crescent moon and lasts 29 or 30 days, which gives a year of about 354 days.

The four sacred months (al-Ashhur al-Hurum) are Dhul-Qi'dah, Dhul-Hijjah and Muharram, three consecutive months, and Rajab, a sacred month on its own. The Quran names these four months, during which fighting was traditionally forbidden and good deeds carry particular weight. Dhul-Hijjah holds the Hajj and Eid al-Adha, Muharram the day of Ashura.

The Islamic calendar is lunar and has about 354 days, some ten days fewer than the solar year. Festivals such as Eid al-Fitr and the start of Ramadan therefore move about 11 days earlier each year in the Gregorian calendar. Over some thirty years they pass through every season, so every Muslim knows fasting in summer as well as in winter.

The Islamic era begins with the Hijra, the migration of the Prophet Muhammad ﷺ from Mecca to Medina in 622 AD. The new year begins on 1 Muharram, the first month of the calendar. Its exact date depends on the sighting of the crescent moon, which can bring slight variations from one country to another, even though astronomical calculation now allows it to be predicted precisely.

The two great festivals are Eid al-Fitr, on 1 Shawwal at the end of Ramadan, and Eid al-Adha, the festival of sacrifice, on 10 Dhul-Hijjah in memory of Ibrahim's sacrifice. To these are added notable dates: Ashura on 10 Muharram, the commemoration of the Isra and the Mi'raj on 27 Rajab, the night of mid-Sha'ban and the Night of Decree (Laylat al-Qadr) in the last ten days of Ramadan.