As a Christian seeking understanding, I’m fascinated by the fluctuation of Hijri dates on the Gregorian calendar. Despite a consistent 24-hour time difference globally, what causes this unique variability in Hijri dates compared to other calendars?


First and foremost, it’s essential to clarify that the commencement of the lunar month is not determined by the Gregorian calendar. Instead, it relies on the sighting of the new moon (Crescent). Allah Ta’ala states in the Noble Qur’an: “They ask you (O Muhammad), about the new moons. Say, they are measurements of time for the people and for Hajj.” (2:189) Regarding the global standardization of the Islamic Hijri calendar, neither the Qur’an nor the Sunnah explicitly mandates the uniformity of lunar month beginnings and endings worldwide. Instead, Muslims are instructed to rely on the sighting of the moon to determine the commencement and conclusion of each lunar month.