هجري
Hijrī
Topic
The Islamic lunar calendar, counted from the Prophet’s migration to Medina in 622.
What it means
It has twelve lunar months of 29 or 30 days, a year of about 354 days, so its months move through the seasons: Ramadan falls about eleven days earlier each solar year. Umar fixed the era from the hijra in 638 (17 AH). The Quran says that “the number of months with God is twelve” (9:36), and condemns postponing months (nasīʾ) as “an increase in disbelief” (9:37).
What the sources say
The month of Dhu al-Qida is one of the four sacred months of truce, and Dhu al-Hijja the month of pilgrimage. The Quran’s ban on adding a month to line the calendar up with the sun explains why Ramadan moves through the year.