Holidays and Regular Observances

What kind of religious calendar do Muslims observe?

Muslims follow a lunar calendar whose twelve months add up to 354 days. In a cycle of thirty lunar years, eleven are leap years, with one day added to the last month. During Muhammad’s time the lunar months were associated with seasons (Ramadan means “extreme heat,” Rabi’ “rainy season,” and Jumada “dry season,” for example). As in the Jewish calendar, the pre-Islamic year maintained its connection with agricultural cycles and seasons by the intercalation of a whole month in certain years. Since the practice of intercalation ended around Muhammad’s time, the Islamic lunar year rotates backward eleven days each year in relation to the Gregorian solar year. If Ramadan, for example, begins on January 12 this year, next year it will begin on January 1, and so on. Certain practical results of this backward rotation are worth noting because of the way timing can affect religious practice. When Ramadan (the ninth month) occurs in the dead of winter, when days are shortest, the fast from sunrise to sunset is less arduous than when Ramadan falls during the height of summer. Pilgrimage to Mecca can also be more strenuous when the season of Hajj (in the twelfth month) occurs during the hottest season. Muslims the world over therefore must learn to work with two different systems of marking special times. Muslims begin their count of years with the Hijra of 622. Approximately every thirty-three years the beginnings of the Islamic lunar and Gregorian solar years roughly coincide.

Date Event
1 Muharram Islamic New Year
10 Muharram Day of ‘Ashura (i.e., “tenth” day) For Sunni Muslims, day of recommended fast (parallel to Jewish Day of Atonement originally). For Shia Muslims, the martyrdom of Husayn ibn Ali, the grandson of Muhammad, and his followers in 680 C.E.
12 Rabi al-Awal Birthday of the Prophet observed by many Sunni Muslims
17 Rabi al-Awal Birthday of the Prophet observed by Twelver Shia Muslims
13 Rajab Birthday of Ali ibn Abi Talib
27 Rajab Muhammad’s Night Journey and Ascension
15 Sha’ban Middle of Sha’ban, or Night of Forgiveness, and the birthday of Muhammad al-Mahdi, Twelfth Shia Imam
1 Ramadan Beginning of month-long fast
21 Ramadan Martyrdom of Ali ibn Abi Talib
27 Ramadan Initial “descent/revelation of the Qur’an,” (observed on the 17th of Ramadan in Indonesia and Malaysia; also known as the “Night of Power”
1 Shawwal Feast of the Breaking of the Fast, closing Ramadan—one of the two greatest festal days
8-13 Dhu al-Hijjah Season of official Hajj to Mecca
10 Dhu al-Hijjah Feast of Sacrifice during Hajj season, recalling God’s command that Abraham sacrifice his son (Isma’il)—second of the two greatest festal days
18 Dhu al-Hijjah Feast of Ghadir Khumm, Shia observance of the Prophet’s designation of Ali as his “caliph”


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