The month of Ramadan 2023 is just a few days away. The holy month will start on March 22, and end with the celebratory Eid al-fitr on April 22 or 23, depending on the citing of the moon. As a person in my late twenties, I remember celebrating Ramadan in winter, summer and rainy season while calendars of other religions are season-dependent. So a puzzling question for a layman can be how the Islamic calendar works.
Calendars are an enigma, there are countless versions varying from religion to religion, region to region. For a lay person, they are difficult to understand or even to put in practice. But a common thread across calendars is that they are all linked to seasons. For example, Dasara, a Hindu festival, is always celebrated in September-October of a Gregorian calendar, although the Hindu calendar is separate and has its unique principles.
But this is not the case of Islamic Hijri calendar, which is followed by close to 2 billion Muslims in this world. This calendar, which is counted from the year the holy migration of the Prophet Muhammad from Mecca to Medina took place, is not linked to seasons. Hijri is derived from the word “hijra,” which in Arabic means departure or migration, referring to the migration of Prophet Muhammad and his followers to Medina.
The Islamic calendar follows its own set of rules independent of seasons. This is the reason we see Ramadan sometimes in the winter season, sometimes in monsoon. Similarly, all Islamic festivals are independent of the seasons. So how does this work?
The Hijri calendar which is followed by all Muslims for religious purposes has 12 months and is based on a lunar cycle, i.e., on the movements of the moon. The calendar begins with the month of Muharram and ends with Dhu Al Hijjah. For non-muslims, the month of Ramadan is the most prominent one.
The Gregorian calendar and other major calendars depend on the movements of the sun or in some instances, both the movements of sun and moon, known as lunisolar. While so, the Hijri calendar depends on the lunar cycle (i.e., the position of the moon alone). A lunar cycle lasts for 29 days, which makes one month in the Hijri calendar while a Gregorian calendar month has 30-31 days. This shortage of 1-2 days every month results in the Hijri calendar having only 354-355 days as opposed to 365-366 days in a Gregorian calendar.
The shortage of days when compared with the Gregorian calendar results in Islamic festivals moving backward in a Gregorian calendar. So this is the reason why Ramadan started on April 2 in 2022 and now on March 22 in 2023. The 2024 Ramadan starts on March 10.
This backward travel of Islamic festivals on the Gregorian calendar results in the festivals being observed on any month of the Gregorian calendar year and is independent of seasons which are again linked to movements of the sun.
For one complete trip through the Gregorian calendar, the Islamic calendar requires 33 years, i.e., it would take another 33 years for Ramadan to fall on similar dates as that of 2023. This unique feature of the Hijri calendar will also result in some English calendar years having two Islamic festivals in the same year. For example, in 2033 we will have Eid celebrated twice in January and December.