Islam is something of a peculiar religion when it comes to festivals in two ways. One, it doesn't have a whole lot of them — at least, not a lot that anyone pays attention to. Two, they are linked to the Islamic calendar, which is purely lunar: it is only 354 days long, or about 11 days shorter than the solar year, with each of its twelve months almost exactly beginning at the day of the New Moon. These two peculiarities are related: because of the length of the calendar, the months move through the seasons, and thus the Islamic year lags behind its Gregorian/solar counterpart.
Since so many festivals elsewhere around the world, civil, cultural or religious, are linked to the solar seasons, it would be very difficult to link them to the Islamic calendar. As a result, while seasonal festivals do exist in many Islamic countries, they tend to be cultural in nature and are linked to local solar/lunisolar calendars, many of which date from pre-Islamic times. For instance, the Egyptian spring festival, Sham el-Nessim, is linked to the Egyptian calendar, which is more or less the same as the old Julian calendar (it falls on Orthodox Easter Monday for historical reasons). By the same token, the Iranian spring festival, Nowruz, falls on the first day of the Persian solar calendar, which is based on both Islamic, Persian and Hindu calendars. Some of these are region-based, such as Basant, which is a famous spring festival (with lots of kites) mostly celebrated in Lahore, Pakistan.
Due to the rather common ignorance of Western media about Islam (most of it unfortunately deliberate), the above warning is very pertinent. If you see Muslims celebrating a certain festival/holiday it is less likely religious than it is cultural. This can be ever more problematic when one looks at the distribution of Muslims in Western countries, with huge sections of migrants from one Islamic region forming a considerable Islamic minority in any Western country. For example, British media may often show Muslims celebrating festivals which are common only in parts of Pakistani Kashmir, which is where most British Muslims hail from.
Another point is that many of these are not "holidays" at all in the sense that they are not days off. As a result, Islamic holidays are fairly few and far between. However, there are several ones worth mentioning.
For reference, the Muslim months are:
- Rabi' al-Awwal (First Rabi')
- Rabi' al-Thani (Second Rabi')
- Jumada al-Awwal (First Jumada)
- Jumada al-Thani (Second Jumada)
- Dhu al-Qi'dah
- Dhu al-Hijjah
The calendar's years are usually titled "Anno Hegirae" (AH, or "Year of the Hegira"), and the reckoning begins at 17 July 622, the first New Moon after The Prophet Muhammad arrived at Medina 15 days earlier, having fled an assassination plot at his native Mecca back on 17 June.
New Year (Ra's al-Sanah al-Hijrīyah) — 1 MuharramA fairly unimportant holiday, which often goes completely unnoticed today. There are only two interesting things about it:
One, its Arabic name sounds like Rosh Hashanah, which is justified as both Arabic and Hebrew are related languages and both terms mean "Head of the Year". The word is also used in Arab countries to refer to the Gregorian New Year (1 January).
Two, there's a story that Muhammad noticed that Jews fast for Yom Kippur in honor of Moses. To show that Muslims also honor him, he started fasting on the first two days of Muharram. Some people continue to observe the fast. That's about it.
Ashura — 10 MuharramA mostly Shi'a holiday, commemorating the defeat and death of Muhammad's grandson Husayn ibn Ali at Karbala in Iraq on 10 Muharram AH 61 (10 October 680). Since they regard Husayn as the rightful Caliph, they understandably regard the day as one of mourning; salty foods (representing salty tears) are eaten, and self-flagellation and other forms of self-injury (including, famously, cutting the forehead with a sword) are some forms of remembrance (self injury is only common in some places). Also, prayer. Lots of prayer.
Sunnis tend to ignore the holiday, although some believe that the aforementioned tradition of fasting on 1-2 Muharram actually applies to 9-10 or 10-11 Muharram; since the custom is based on a report of something the Prophet did, it's not unexpected that there are conflicting reports. This corresponds more closely to the date of Yom Kippur (10 Tishri), as Muslim months almost always start on the same day as Jewish months, as the latter calendar is lunisolar. There is also a cultural custom in Egypt and Turkey to eat a certain kind of pudding with nuts and dried fruit, also called Ashura, on that day; what it has to do with anything is unclear.
Bizarrely, the festival has also spread to the Anglophone Caribbean, particularly Trinidad and Tobago and Jamaica, where it is known as Hosay (after Husayn), brought by Shi'a workers from British India, and was adopted by Hindu Indians as well as a gesture of cultural solidarity. Eventually, the practice became much more widespread; it is celebrated with the construction of impromptu mosques out of paper and tinsel, along with a lot of balloons. The practice is by no means universal, but it has seen a revival in recent years.
Arba'een — 20 SafarAnother strictly Shi'a holiday, commemorating the fortieth day after Ashura (the name literally means "forty" in Arabic, forty days being the traditional period of mourning in Middle Eastern cultures, which was also passed down onto Judaism and Christianity). A common date for Shias to go on pilgrimage to Karbala, where Husayn fell and was buried. An interesting trivia is that Arba'een regularly attracts more than 30 million people each year, making it the second largest annual gathering in the world. In fact, Arba'een attracts more people than the Hajj, the holiest season in Islam, even though unlike the Hajj, it is not religiously mandated.
Mawlid an-Nabi (Birthday of the Prophet) — 12/17 Rabi' al-AwwalA holiday whose importance varies from place to place. In some countries, it's a big deal, a full day-off with parades and special prayers and so on.note In others, like Saudi Arabia, it is banned. There is a long and complicated theological debate about this, with ulema (religious scholars) having some pretty heated arguments about whether it is allowed or not; those in support mostly do so in veneration of the Prophet, while those against regard the holiday as an unnecessary innovation (bid'ah). In general, however, the holiday is more uniformly regarded as sacred for the Shi'a, due to their emphasis on veneration of the Prophet's family. There is also a difference over the date: Sunnis and some Shi'a sects recognize the twelfth of Rabi' al-Awwal, while most Shi'a recognize the seventeenth.
Birthday of Ali ibn Abi Talib — 13 RajabA minor commemoration for Muhammad's cousin, son-in-law and first young convert, revered by both Sunnis and Shi'a: to the former as the fourth and final Rashidun ("Righteously Guided") Caliph, after Abu Bakr (Muhammad's father-in-law, his very first convert and advisor), Umar ibn Al-Khattab (disciple and jurist) and Uthman ibn Affan (another son-in-law); and to the latter as the first of the Twelve Imams, all of whom are direct descendants of Muhammad.
Isra and Mi'raj — 27 RajabCommemorates the night when Muhammad, according to tradition, was transported to Jerusalem on a winged horse, met and prayed with all of the prophets, and then was lifted up to heaven to have a personal chat with God, receiving some commandments in the process. Although pretty much all Muslims know the story, very few commemorate it at all, and many aren't even aware the holiday exists. Those who do know about and observe the holiday tend to restrict their celebration to an extra prayer at night, although in some places they string lights up around town and tell the story to young children, attracting them to the mosque with candy.
Nisf Sha'ban — 15 Sha'banLiterally "Mid-Sha'ban", this has no particular religious significance, but it is widely seen as good time to start warming up for Ramadan. Observant Muslims tend to go on a voluntary fast on this day, and stay up late or even all through the night, praying. These are both activities associated with Ramadan, so it makes a fair amount of sense. Some continue to do this for the rest of Sha`ban, while some might only fast a few more days between the 15th and the first day of Ramadan.
Shi'a also celebrate 15 Sha'ban as the birthday of Muhammad al-Mahdi, the twelfth and final Imam, who is predicted to return to bring the whole under Islam after centuries of hiding.
Ramadan (the whole month)Not so much a holiday or a festival as a duty. Able-bodied, adult, non-poor Muslims must fast from dawn to sunset — no food, no drinks, no smoking, no sex, and no evil thoughts. You also must be in clean state while performing it, so women in period or just after giving birth are not allowed to fast, having to make it up later. This is meant to foster holiness and solidarity with the poor (Muhammad was a poor orphan, and social justice was one of his platforms). Muslims are also supposed to perform the tarawih, in which the whole Qur'an should be prayed through the whole month; to make this easier, the Qur'an has been divided into thirty parts of roughly equal length, though given its relative brevity compared to most religious texts, the task is actually fairly manageable.
Ramadan tradition varies around the Muslim world. In some places, mosques and rich people put out big tables full of food for the poor; sometimes, the food can be quite rich.note
The intersection of Ramadan and modernity has also created a fair amount of Fantastic Religious Weirdness. The most obvious thing is that there are now Muslims all over the world, which has an effect on the dawn-to-dusk requirement: Muslims in high-latitude regions enjoy short and easy fasts in winter, but suffer long and hard ones in summer. Various ulamas have advised their laity to fast for exactly twelve hours, to fast for the hours as in Mecca (which is low-latitude and thus has 11-13 hours of sunlight), or to simply suck it up. Wealthy Gulf Arabs, among others, have been known to jet off to high-latitude places experiencing winter for a shorter fast, much to condemnation by some clerics.
Still other weirdness comes from the nature of modern work. Since fasting can seriously drain one's energy, many Islamic countries provide for shortened work hours during Ramadan. Some businesses just close during the day and operate at night. As a result, many spend the month at their houses watching TV, particularly soap operas. Indeed, many soaps in the Middle East are made specifically for Ramadan — since Arab, Turkish and Iranian soaps tend to be of the Latin American School, this works quite well.
Laylat ul-Qadr (The Night of Power) — 19/21/23/25/27/29 RamadanThis is a very religious holiday, with multiple significance. It marks the beginning of the revelation of the Qur'an to Muhammad, and is also supposedly the day on which the fate of everything in the world is sealed for the year (rather like the Jewish belief about Yom Kippur). It is generally accepted practice to pray all night that day; even men who don't show up for tarawih often go to the mosque on this night. Some very devout people move into the mosque for the last ten days of Ramadan, spending all their time praying and reading the Qur'an, except when they have to sleep or eat. This is because there is no consensus on when the holiday takes place, with the only hint being that it takes place on an odd day of the last ten days. Combined with the belief that praying during the holiday will net you a thousand more rewards than during an ordinary day and you get the idea why devout people would do such thing.
Chaand Raat (Night of the Moon) — 29/30 RamadanA predominantly South Asian festival held on the eve of Eid al-Fitr, when people gather together to spot the New Moon, with celebrations sometimes being comparable to Christmas Eve.
Eid al-Fitr (Feast of the Breaking of the Fast) — 1 ShawwalOne of Islam's biggest festivals, celebrating the end of Ramadan, is marked with a wide array of festivities and rituals. As is typical for a Muslim holiday, it is associated with certain religious observances, chief among them are Zakat ul-Fitr and Salat al-Eid. The former is a donation for the poor, required for anyone who can afford it. The latter is a large group prayer — in many places, people have to pray in the street because the mosque is too crowded — with certain extra rituals and (often) an extra-long sermon. These are usually carried out in the early-to-mid-morning, well after sunrise: you have to give people time to eat while the sun is up (remember, something they haven't been able to do in a whole month). Everybody typically wears their best clothes.
The rest of the day is typically devoted to all kinds of fun: inevitably, there's a truly massive family feast in which everyone pulls out all the stops, typically sometime in the afternoon. Snacking, particularly on sweet foods, is common all through the day. Children are traditionally given gifts and/or money. And no matter where you go in the Muslim world, every culture has its own unique sort of public festivity. In Muslim Southeast Asia (e.g. Indonesia, Malaysia), for example, Eid al-Fitr is the holiday of the year, with the government designating an entire week before and after the holiday off to handle the rush hour of people migrating between the big cities and their home sweet home. It's Serious Business of the same kind that Christmas receives in Christian countries.
First Day of the Hajj — 8 Dhu al-HijjahThe starting date for the most important duty of able-bodied Muslims: to make a pilgrimage to Mecca at least once in their lifetimes. After the morning (Fajr) prayer, pilgrims go to Mina, a valley outside Mecca where they spend the entire day praying. To accommodate the number of people visiting, the Saudi government set up millions of white tents in the place, so Mina is also known as the "Valley of Tents".
Though the hajj technically only lasts five days (8 to 13 Dhu al Hijjah), the procession is usually taken to mean from the start of the month, so pilgrims arrive a week early to begin the Hajj preparations. Many Hajj package tours also add more days after the season ends, mostly consisting of tours to Medina (Islam's second holiest city, where the Muslim community was first organized and where the Prophet Muhammad was buried), thus extending the stay. Managing millions of people visiting during a very specific time of the year is a herculean task, hence why Hajj is so outrageously expensive (US$5,000 is the average minimum price for a single person). Saudi Arabia also imposes quota on the number of pilgrims; it's not uncommon for people to queue for decades before their request is accepted.
Note that it is perfectly okay for you to visit Mecca for pilgrimage any day of the year, but it would only count as an Umrah (meaning visitation) and does not count as a Hajj. Since Umrah has no schedule, it is way cheaper than the Hajj (it costs, on average, half a Hajj) so many people take it as a preparation for the real thing. To do Umrah, one simply have to do Tawaf (circumambulating the Kaaba, that cube-shaped thing in the middle of the Masjid al-Haram, seven times counterclockwise), perform prayers at the Place of Ibrahim (Abraham), and do the Sa'ay ritual, where pilgrims run between the hills of Safa and Marwa seven times, reenacting Hajar (Hagar)'s search for water for her son, Isma'il (Ishmael). The extra acts performed during the Hajj season are not required.
Day of Arafah — 9 Dhu al-HijjahThe eve of Eid al-Adha and second day of the Hajj, when pilgrims start climbing Mount Arafat, about 20 kilometers (18 miles) east of Mecca, where Muhammad preached his last major sermon. At sunset, the pilgrims leave Arafat for Muzdalifa, an open air area between Arafat and Mina, where they spend the night sleeping under the stars.
Eid al-Adha (Feast of the Sacrifice) — 10-13 Dhu al-HijjahThe biggest festival of the Muslim year, as indicated by its length (four whole days, although most folks only get the first day off), commemorating Ibrahim nearly sacrificing of his son Isma'il on God's orders, only to be immediately substituted with a lamb. Sounds familiar? The Bible has the same story, except that it's Isaac (Ishaq in Arabic) who was nearly sacrificed. Significantly, Ishmael is legendarily one of the ancestors of the Arabs, and of Muhammad's Quraysh tribe in particular, while Isaac was of course the patriarch of the Hebrews. So there's that. The feast marks the end of the Hajj and is performed like a restrained Eid ul-Fitr. People offer Salat al-Eid and eat lots of good food.
Anyone who can afford it are required to sacrifice an animal (traditionally a lamb or a sheep, but in some places goats or camels would suffice, while some rich people offer up cows). Since personal involvement is optional, most people pay a butcher to do the ritual for them, after which they eat at least part of that sacrifice, which becomes the centerpiece of the inevitable feast. Some wealthier families can also distribute some of their sacrifice to the poor.
For Hajj pilgrims, they are required to go to Mina, where they perform the symbolic Stoning of the Devil (Ramy al-Jamarat). Pilgrims throw seven stones at the largest of three pillars at Mina, before slaughtering an animal (most Hajj tours pre-include this already, so pilgrims don't need to show up physically for the sacrifice), shaving their hair, then performing a Tawaf. The other two pillars are stoned in 11 and 12 Dhu al-Hijjah. On the last day of the Hajj, pilgrims perform a Farewell Tawaf. As noted above, many Hajj package tours include an additional visit to Medina, so foreign pilgrims don't necessarily leave Saudi Arabia immediately after this.