Unlike the Christian/ Gregorian calendar used in the majority of countries in the West which is based on the movement of the sun, the Islamic calendar follows a lunar structure, basing the length of is months on the movement of the moon.
The Islamic calendar dates back not to the birth of the Prophet Muhammad, as mistakenly believed by many, but to the year of the Hijrah, or migration the city of Madinah from Makkah by the Prophet Muhammad and his followers in 622 CE., the year of the Islamic Calendar is the current Gregorian year minus 622.
As the Islamic calendar is lunar, it is consequently around 10 days shorter than the Gregorian calendar meaning that the months of the two calendars do not directly correspond.
Similar to the Christian calendar, the Islamic calendar has 12 months, which are as follows:
3 Rabbi Al-Awwal
4 Rabbi Al-Thani
5 Jumad Al-Ula
6 Jumad Al-Ukhra
11 Dhul Qa’dah
12 Dhul Hijjah
Many of these months have special religious significance. Ramadhan, for example, perhaps the most famous month of the calendar, is the month during which Muslims all over the world fast from sunrise to sunset.
Dhul Hijjah is also important as this is the month in which Muslims make the annual pilgrimage to Makkah, known as Hajj.