The Islamic Lunar Calendar – Hijri Calendar

Comparing the Gregorian Calendar with the Muslim Calendar

Dec 30, 2009
Christine Benlafquih

The Phases of the Moon Determine a Lunar Month - Jason Weeks, stock.xchng

The Islamic lunar calendar has twelve months. How does the Muslim Hijri calendar differ from the Gregorian solar calendar?

At the time of Islam's emergence in the 7th century, a number of different calendars were in effect around the world. While most of these calendars were solar, some lunar and lunisolar calendars had also been created and implemented. All of these calendars had differing starting dates, or epochs.

The inconsistency in the various calendars eventually became an issue for the early Muslims, who found it difficult to uniformly record dates on correspondence and documents within the expanding Muslim world.

The Hijri Calendar (Islamic Lunar Calendar)

To solve this problem, as well as to establish a dating system which marked Islamic holy months and holidays, the second Muslim caliph Umar ibn Al-Khattab (may Allah be pleased with him)* ordered that an Islamic lunar calendar be established in 638 AD. The 12 months in the Muslim calendar, and the use of the lunar cycle as its measurement of time, were determined by verses in the Qur'an:

"Verily the number of months with Allah is twelve months, so was it ordained by Allah on the Day when He created the heavens and the earth...." (Qur'an 9:36).
"It is He Who made the sun a shining thing and the moon as a light, and measured out for it stages that you might know the number of years and the reckoning. Allah did not create this but in truth. He explains the ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) in detail for people who have knowledge." (Qur'an 10:5).

The Muslims' historic migration from persecution in Mecca to safety in Medina some 16 years earlier served as the starting date for the new Islamic calendar. Accordingly, the name for the Muslim calendar – hijri – was taken from the Arabic word for migration, hijrah. The date of the Muslim calendar's epoch corresponds to July 16, 622 AD on the Gregorian calendar.

The Difference Between the Gregorian Solar Calendar and the Islamic Lunar Calendar

Both the internationally-accepted Gregorian calendar and the Islamic Hijri calendar have 12 months. The two calendars differ, however, in that the Gregorian calendar divides its months into a solar year, while the Islamic calendar divides its months into a lunar year.

The Islamic Hijri calendar correlates the number of days in each month to the regular lunar phases. When a new crescent moon is sighted every 29 or 30 days, a new lunar month begins. The result is a 12-month lunar calendar year with months synchronized to the lunar cycles.
The Gregorian solar calendar, in contrast, adjusts the length of 12 months so that they are synchronized with a solar year and the seasons. This enables the Gregorian months to consistently fall within the same seasons each year.

The Islamic Hijri lunar year is 354 or 355 days long, making it 10 or 11 days shorter than the 365-day Gregorian solar year. For this reason, Islamic months and holidays do not fall within the same seasons each year. It takes approximately 33 years for the Hijri lunar months to make a complete rotation through the seasons.

Names of the Islamic Lunar Months

The names of the Islamic lunar months in the Hijri calendar are listed below. Each Islamic new year commences on the first day of the Islamic month of Muharram. Asterisks indicate holy months when Muslims are forbidden from fighting and encouraged to avoid unlawful acts.

Muharram*
Safar
Rabia Awal (I)
Rabia Thani (II)
Jumada Awal (I)
Jumada Thani (II)
Rajab*
Sha'ban
Ramadan
Shawwal
Dhul Qi'dah*
Dhul Hijjah*

Although the Gregorian calendar is officially used throughout the world, in many Muslim countries the Gregorian and Hijri calendars are used side-by-side. Muslims are encouraged, however, to give preference to the Islamic lunar calendar as much as possible.