The Structure of the Lunar Calendar
How it works: Each month begins with the confirmed sighting of the new crescent moon (hilal). The month is 29 or 30 days depending on when the moon is sighted. A year is 12 lunar months = 354 or 355 days. Because this is approximately 11 days shorter than the Gregorian year, Islamic occasions rotate through all Gregorian months over a 32-33 year cycle.
Why lunar?: The Quran explicitly rejected the pre-Islamic practice of nasi’ (intercalation — adding an occasional 13th month to realign with the solar year, as the Jews do with their lunar-solar calendar): “Indeed, the postponing [of restriction within sacred months] is an increase in disbelief by which those who have disbelieved are led [further] astray. They make it lawful one year and unlawful another year to correspond the number of months sanctified by Allah and [thus] make lawful what Allah has forbidden.” (9:37) The purely lunar calendar was thus established as divine command.
The start of the year: The Hijri calendar was formally established during the caliphate of ‘Umar ibn al-Khattab (RA), in approximately 17 AH (638 CE), when the need for administrative dating became pressing. The Companions chose the Hijra as the epoch rather than the Prophet’s birth or the beginning of revelation, establishing that the community (ummah) as a social reality is the proper basis for Islamic historical reckoning.
The Twelve Months and Their Significance
1. Muharram — The Sacred Month of New Beginnings
Position: First month; one of the four sacred months in which fighting was forbidden in pre-Islamic and Islamic tradition.
The 10th of Muharram — ‘Ashura’: The most significant day. The Prophet (SAW) found the Jews of Medina fasting on this day and asked why; they said it was the day Allah saved Musa from Pharaoh. The Prophet (SAW) said: “We have more right to Musa than you do” — and fasted it himself, and commanded fasting one day before or after to distinguish from Jewish practice. For Shia Muslims, ‘Ashura’ is the day of the martyrdom of Imam Husayn ibn ‘Ali at Karbala (61 AH / 680 CE) — a day of mourning, not fasting. In the Bohra tradition, ‘Ashura’ (the first 10 days of Muharram) is a period of intense devotional observation. (See [[ashura-karbala-commemoration]])
2. Safar — The Month of Travel
Historically associated with travel and military campaigns. Pre-Islamic Arabs considered it an unlucky month — a superstition the Prophet (SAW) corrected: “No ‘adwa, no tiyara (bad omen), no hama (bad luck from an owl), no safar [as a month of bad luck].” (Bukhari)
3. Rabi’ al-Awwal — The Month of the Prophet’s Birth and Death
The month in which the Prophet (SAW) was born (and also died) — on the 12th, according to the majority scholarly opinion. The Mawlid al-Nabi (celebration of the Prophet’s birth) is observed in this month across much of the Islamic world. (See [[mawlid]])
4. Rabi’ al-Thani — The Second Spring
The month completes the “first spring” period. No major specific events.
5. Jumada al-Ula — The First Freezing
The name refers to a period of water freezing in pre-Islamic Arabia. No major specific events.
6. Jumada al-Akhira — The Last Freezing
The Battle of Mu’ta (8 AH) occurred in this month — the first major engagement between the Muslim army and the Byzantine Empire.
7. Rajab — The Sacred Month of the Isra’ and Mi’raj
One of the four sacred months. The 27th of Rajab is traditionally held to be the date of the Isra’ and Mi’raj — the Prophet’s night journey to Jerusalem and his ascent through the heavens. (See [[israa-miraj]], [[mawlid]]) The Bohra community observes Laylat al-Isra’ wa’l-Mi’raj on this night.
8. Sha’ban — The Month Before Ramadan
The Prophet (SAW) fasted more voluntary fasts in Sha’ban than any other month outside Ramadan: “That is a month between Rajab and Ramadan that people neglect — it is a month in which deeds are raised to the Lord of the Worlds, and I love my deeds to be raised while I am fasting.” (Nasai) The 15th of Sha’ban (Laylat al-Nisf min Sha’ban — the Night of Mid-Sha’ban) has special devotional significance in many traditions.
9. Ramadan — The Month of Fasting, Quran, and ‘Ibada
The ninth month and the holiest month: “The month of Ramadan in which was revealed the Quran, a guidance for the people and clear proofs of guidance and criterion.” (2:185) The entire month is obligatory fasting from Fajr to Maghrib. The last ten nights include Laylat al-Qadr (the Night of Power — better than a thousand months). Salat al-Tarawih (20 raka’at) is the special night prayer of Ramadan. The month ends with Eid al-Fitr. (See [[fasting-rules]], [[zakah-al-fitr]])
10. Shawwal — The Month of Eid al-Fitr
The first of Shawwal is Eid al-Fitr — the Festival of Breaking the Fast. The Prophet (SAW) recommended fasting 6 days of Shawwal after Eid (not consecutively required): “Whoever fasts Ramadan then follows it with 6 days of Shawwal, it is as though he fasted the entire year.” (Muslim)
11. Dhul-Qa’da — The Sacred Month Before Hajj
One of the four sacred months. Pilgrims begin departing for Mecca in this month. No major specific events.
12. Dhul-Hijja — The Month of Hajj and Eid al-Adha
The last and arguably most blessed month: the Prophet (SAW) said the first 10 days of Dhul-Hijja are the best days of the year for ‘ibada. The 8th-13th constitute the Hajj season. The 10th is Eid al-Adha (the Festival of Sacrifice) — when pilgrims and Muslims worldwide sacrifice animals. The 9th is the Day of ‘Arafat — fasting on this day expiates two years of minor sins. (See [[hajj-types]], [[mina-and-rami]])
The Four Sacred Months
The Quran mentions four sacred months (al-ashhur al-hurum): “Indeed, the number of months with Allah is twelve… of these, four are sacred.” (9:36) They are: Muharram (1st), Rajab (7th), Dhul-Qa’da (11th), and Dhul-Hijja (12th). Fighting was forbidden in these months, and sins committed in them carry greater weight — as does worship performed in them.
See also: Fasting Rules, Hajj Preparation, Ashura Karbala Commemoration, Mawlid, Israa Miraj, Zakah Al Fitr, Seerah Medina