Days & Dates of Islamic Significance in the Year

السلام عليكم ورحمة الله وبركاته

بِسْمِ اللهِ الرَّحْمٰنِ الرَّحِيْم

The Islamic religious year is known as Hijri year. It began with the Hijrah of the Prophet Muhammad (PBUH) from Makkah to Madinah in the year 622 of the common era. The twelve-month year is based on a purely lunar cycle of 354 days. Thus Islamic dates have no fixed relation to the seasons of the 365 day solar year. Over the course of years all Islamic events may occur in spring, summer, autumn or winter.

Twelve Islamic months are as follows:

1. Muharram ul Haram
2. Safar
3. Rabi-ul-Awwal
4. Rab-ul-Akhir
5. Jamadi-ul-Awwal
6. Jamadi-ul-Akhir
7. Rajab
8. Sha'aban
9. Ramadhan
10. Shawwal
11. Dhul Qadah
12. Dhul Hijjah

Important Days:
Following are the most important religious days in Islam:

• Friday:

This is the main day of weekly religious service in Islam. Mosques are usually filled to capacity with worshippers on this day. Worship service which consists of sermon and congregational prayer is held around noon time. In most Muslim countries Friday is also a weekly holiday. Government offices and schools are closed on this day.
Muslims respect Friday because, according to Islamic tradition, it was the first day of creation when God created the heavens and earth. It is also believed to be the day when the resurrection will take place and so it will be the Day of Judgment. Muslims believe that Friday has a special cosmic significance and it is a very blessed day of the week.

• Ramadan (9th month):

Ramadan is the ninth month of Islamic lunar calendar. Muslims consider this whole month a blessed month. They fast during the days of this month and make special prayers at night. People also give more charity and do extra righteous deeds.
During the month of Ramadan, Prophet Muhammad received the first revelation. The angel Gabriel came to him while he was in the cave of Hira, near Makkah, and told him that God had appointed Muhammad as His last Messenger and Prophet. Muhammad began his prophetic mission from that time and started preaching the divine message that continued coming to him at different intervals during the rest of his life for 23 years. Ramadan is thus the month of celebration as well as the month of discipline and self control.

• Laylat al Qadr:

This is a special night of the month of Ramadan. The Qur'an has spoken about this night in Surah 97, al Qadr. It is mentioned that the Qur'an was sent down in the Night of Qadr. The Night of Qadr is better than one thousand months. The whole night is blessed, it is full of peace and angelic presence. Although it is not told exactly which night of the month of Ramadan is the Night of Qadr, Muslim make special prayers in the last ten nights of the month of Ramadan, hoping that one of it is the blessed Night of Qadr.
Popularly the night of the 27th of Ramadan is celebrated with special prayers and vigils. Mosques are full of worshippers and special prayers services, readings from the Qur'an and religious chants are performed in mosques or private gatherings.

• Eid-ul-Fitr (1st of Shawwal, 10th month):

At the conclusion of the month of Ramadan, on the first day of the 10th month of Islamic lunar calendar occurs Eid-ul-Fitr. This is one of two main festivals of Islam and is celebrated by all Muslims throughout the world
The ceremony of Eid-ul-Fitr starts early morning with a worship service. This service is generally held in a large open place and is attended by thousands of Muslims. After the prayer the leader of the prayer (Imam) delivers a short sermon and then people greet each other. The rest of the ceremonies are held generally privately with families and friends.
The significance of Eid is that it is a day of thanksgiving to Allah that He gave the opportunity to Muslims to benefit from and enjoy the blessings of the month of Ramadan.

• The Day of Hajj (9th of Dhul Hijjah, 12th month):

Pilgrimage (Hajj) is one of the five pillars of Islam. Every adult Muslim who can afford it physically and financially must perform Hajj at least once in his/her life. The Hajj takes about five days, beginning from the eighth day until the twelfth . The twelfth month of Islamic year is named after Hajj and is called Dhul Hijjah.
Hajj ceremonies take a pilgrim from Makkah to its surrounding historical places Mina, `Arafah and Muzdalifa. The main day of Hajj is the 9th day of Dhul Hijjah. On this day all pilgrims must gather in the valley of `Arafah from mid day until sunset. Muslims in other places who are not on pilgrimage often observe this day of `Arafah with fasting. It is an optional fasting and is considered very meritorious.

• Eid-ul-Adha (from 10 12 of Dhul Hijjah, 12th month):

Following the day of Hajj comes Eid-ul-Adha. It begins from the 10th day of the 12th month of the Islamic lunar calendar. This is the second main annual festival in Islam. On this day also exactly like the previous celebration, festivities begin with a prayer service held in an open place in the morning of the first day. This prayer is attended by a large number of Muslims. Since this festival occurs immediately after the Day of Pilgrimage those who go to make pilgrimage celebrate it in Mina, near Makkah. Other Muslims around the world also join with the pilgrims in their joy and thanksgiving.
Another significance of Idul Adha is that it is a time of sacrifice. Muslims commemorate Prophet Abraham's willingness to sacrifice his son, Ishmael. Since God gave Prophet Abraham (peace be upon him) a lamb to sacrifice instead of sacrificing his only son, Muslims also offer the sacrifices of animals. The sacrifice can be done after the prayer on the 10th until the 12th before sunset. The meat of the animals is given to needy people and friends and a portion of it is also kept for one's own consumption. Often people cook this meat during the holidays, make feasts and enjoy the celebration.

Other important days:
The above days are universally recognized by all Muslims. There are some other important days that are often celebrated by Muslims with varying degrees of enthusiasm and devotion. Some Muslims do not consider them as religious holidays at all.

• New Year Day (First day of Muharram, 1st month):

The New Year Day of Hijrah reminds Muslims of the Hijrah (migration) of the Prophet Muhammad peace be upon him - from Makkah to Madinah in the year 622. It is well known that the Hijrah did not take place on the first day of Muharram, it probably occurred in the month of Rabi'ul Awwal (3rd month). Also the Hijri calendar was instituted some time in the reign of Caliph 'Umar (634 644 C.E.). However, due to the association of Islamic calendar with Hijrah, new year day becomes an important day to remember the meaning and significance of Hijrah.
In modern times, some Muslims also began using it to send greeting cards and celebrate new year. There are, however, no religious services associated with this day.

• Ashura (10th of Muharram, 1st month):

After his arrival in Madinah in the year 622, Prophet Muhammad - peace be upon him instituted fasting on the 10th of Muharram. A year later this fasting was replaced with the mandatory fasting in the month of Ramadan. However, fasting on `Ashura' remained a voluntary fasting. Many Muslims usually fast on this day also.
This day is also associated with the martyrdom of Prophet Muhammad's grandson Hussain ibn Ali. He was killed in the battle of Karbala' on the 10th of Muharram in 61 A.H. (October 10, 680 C.E.). It is a day of sadness for all Muslims. Shi'ahs in particular attach a great significance to this day and mark this day and the whole month of Muharram with mourning. Special gatherings (majalis) are held to remember the suffering of the Imam and his family and the events that led to Karbala'.

• Maulid al Nabi (12th of Rabi'ul Awwal, 3rd month):

This day is remembered as the Birthday of the Prophet peace be upon him. It is a very popular day of celebration. It, probably, began early in the Fatimid Egypt (beginning of tenth century C.E.) where people began distributing sweets and making special chanting and festivities on this day.
There are no special prayers or religious services associated with this day, but many Muslims use this day to talk about the Prophet, his life and example. They use it as a time to express their love and devotion for Prophet Muhammad. It is now celebrated with varying degrees of enthusiasm throughout the Muslim world and wherever Muslims live. Some people, however, criticize it because it has no sanction in the Qur'an and the Sunnah of the Prophet and the early community (salaf) did not mark this day with any special festivities.

• Night of Isra' and Mi'raj (27th of Rajab, 7th month):

Night journey of the Prophet Muhammad peace be upon him from Makkah to Jerusalem and then his ascension to Heavens occurred in the year 620 C.E. It is mentioned briefly in the Qurán (Surah 17 and 53). The Hadith literature gives much more details of this experience of the Prophet.
Muslims remember this day as a day of great miracle and honor of the Prophet. On the eve of the 27th of Rajab, gatherings are held in the mosques and homes to remember the event and the whole story is told in poetry, chants or lectures. Sweets are distributed and great happiness and joy is expressed.
There are also no special prayers associated with this night. Muslims remember this day with varying degrees of enthusiasm and devotion. Some people do not celebrate it at all.

• Night of the Middle of Sha'ban (15th of Sha'ban, 8th month):

There are all kinds of legends associated with this night. In some countries it is celebrated with firework.
People make special prayers at night and consider it a "night of destiny". There are no authentic ahadith about this night. There are, however, a number of weak (da`if) ahadith that mention that the Prophet Muhammad peace be upon him - used to make special prayers on this night. He used to visit the Cemetery of Muslims and pray for those who passed away and used to fast the following day. The cumulative effect of these ahadith make them acceptable to some. On the basis of these reports some consider fasting on this day a blessed act. Again, this night and its following day are not universally accepted by all Muslims.

Source: Qur'an & Hadith Group