Islamic calendar

The Islamic calendar is a purely lunar one.

In A.D. 638, Umar ibn Al-Khattab[?] (A.D. 592-644) Raa introduced the calendar as a way of consolidating the various calendars then in common usage among Muslim peoples. The years are measured from the date when Muhammad migrated to the city of Medina, on July 16, A.D. 622. The calendar is also called the Hijri Calendar as this migration is called the Hegira. The first day of the first month (1 MuHarram) of the first year (1 AH) is this day. Dates in this calendar are usually abbreviated using AH from the latinized phrase Anno Hegirae, "in the year of the Hegira". Years before the Hegira are denoted BH: there is no year zero.

The predecessor to the Islamic calendar was similar to the Hebrew calendar in that it was primarily lunar but was kept synchronized with the tropical year (that is, based on the motion of the sun) by the insertion of an additional month when required. In the 9th year after the Hejira[?] or migration to Medina, Muhammad forbade the insertion of the additional months.

This is expressed in the 9th chapter and 37th verse of the Quran as:

Verily the transposing (Of a prohibited month) is an addition to Unbelief: The Unbelievers are led to wrong thereby: for they make it lawful one year, and forbidden another year, of months forbidden by Allah and make such forbidden ones lawful. The evil of their course seems pleasing to them. But Allah guideth not those who reject Faith.

This means that the Islamic calendar is always shorter than the Gregorian year by about 11 days, and the days of the calendar are not tied to a specific season of the year. It takes a 33 year cycle of lunar months until a complete traversal of the seasons occurs so that a month will fall again during the same season.

Of all the months in the Islamic calendar, Ramadan is the most sacred, and all Muslims are required to fast during the daytime.

The Islamic months are named as follows:

1. Muharram ul Haram (or shortened to Muharram) محرّم
2. Safar صفر
3. Rabi-ul-Awwal رابي
4. Rab-ul-Akhir (or Raby` al-THaany) رابي الثااني
5. Jamadi-ul-Awwal جومادا
6. Jamadi-ul-Akhir (or Jumaada al-THaany) جمادي الثاني
7. Rajab رجب
8. Sha'aban شا
9. Ramadhan رمضان
10. Shawwal شوّال
11. Dhul Qadah دل كاداه (or Thw al-Qi`dah)
12. Dhul Hijja دل هيجا (or Thw al-Hijjah)

The names of the days of the week

• yaum al-ahad يوم الأحد
• yaum al-ithnayna يوم الإثنين
• yaum ath-thalatha' يوم الثُّلَاثاء
• yaum al-arba`a' يوم الأَرْبعاء
• yaum al-hamis يوم خَمِيس
• yaum al-jum`a يوم الجُمْعَة
• yaum as-sabt يوم السَّبْت

The number of days in each month is not set. Rather, each month begins at sunset on the day of the first sighting of the lunar crescent following a new moon. Traditionally, this requires a sighting by a human observer, and this practice is still followed in many parts of the world. In some countries near the Persian Gulf, the process is simplified by beginning each month at sunset on the first day that the moon sets after the sun. In Egypt, the month begins at sunset on the first day that the moon sets at least five minutes after the sun. These simplifications allow the calendar to be determined in advance, which it cannot be by the traditional method.

The Holy Quran, in the fifth chapter and 36th verse mentions the calendar (translated into English) states: "The number of months with Allah has been twelve months by Allah's ordinance since the day He created the heavens and the earth. Of these four are known as sacred; That is the straight usage, so do not wrong yourselves therein, and fight the Pagans. "

These four sacred months are: Muharram, Rajab, Dhul Qadah and Dhul Hijja. It is from this verse that it is commonly believed that fighting during sacred months is a sin.

Extremely important dates in the Islamic (Hijri) year are:

• 1 MuHarram (Islamic new year)
• 27 Rajab (Isra & Miraj)
• 1 RamaDHaan (first day of fasting)
• 17 RamaDHan (Nuzul Al-Qur'an)
• Last 10 days of RamaDHaan which include Laylatu al-Qadar
• 1 SHawwal (`iyd al-fiTr)
• 8-10 Thw al-Hijjah (the Hajj to Makkah)
• 10 Thw al-Hijjah (`iyd al-'aDHHaa').

The Islamic Calendar years of 1421 and 1422 occur in the Gregorian calendar year of 2001. January 1, 2001 is the day of 6 Shawwal of 1421 AH. 1 MuHarram 1422 AH is March 26, 2001.