Islamic holidays

There are two official^{[according to whom?]} holidays in Islam that are celebrated by Muslims worldwide: Eid al-Fitr and Eid al-Adha. The timing of both holidays are set by the lunar Islamic calendar, which is based upon the cycle of the moon, and so is different from the more common, European, solar-based Gregorian calendar. Every year, the Gregorian dates of the Islamic holidays change.

Both Eid al-Fitr and Eid al-Adha follow a period of 10 holy days or nights: the last 10 nights of Ramadan for Eid al-Fitr, and the first 10 days of Dhu al-Hijjah for Eid al-Adha. The Night of Power (Arabic: لیلة القدر, romanized: Laylat al-Qadr), one of the last 10 nights of Ramadan, is the holiest night of the year.^{[citation needed]} Conversely, the Day of Arafah, the day before Eid al-Adha, is the holiest day of the Islamic year.^{[citation needed]}

There are a number of other days of note as well as festivals, some common to all Muslims, others specific to Shia Islam or branches thereof.

Additionally, Friday is considered the holiest day of the week, and in Islamic tradition, is considered a celebration in itself. Friday Prayers (Juma) are congregational prayers held in mosques, and Muslims are encouraged to wear clean and refined clothes, perfume, and bathe. It is customary to eat special meals with family on this day.