Explained
It is calculated astronomically in advance and can differ by a day from moon sighting in some months. A Hijri year is about eleven days shorter than a Gregorian one.
The Umm al-Qura calendar is the official Hijri calendar in Saudi Arabia, used for government transactions and residence permits.
It is calculated astronomically in advance and can differ by a day from moon sighting in some months. A Hijri year is about eleven days shorter than a Gregorian one.