Why does Islam use a lunar calendar, and why is it significant?

The Islamic, or Hijri, calendar is lunar, following the moon's phases rather than the sun's cycle, and this is explicitly rooted in the Quran. Allah states that "the number of months with Allah is twelve months, [as] written by Allah the day He created the heavens and the earth," establishing the lunar month as the intended basis of Islamic timekeeping since creation (9:36). Elsewhere the Quran explains that Allah "made the moon a light and determined for it phases, that you may know the number of years and account [of time]" (10:5), directly connecting the visible moon to the practical purpose of tracking months and years. Because the lunar year is about eleven days shorter than the solar year, occasions such as Ramadan and Hajj rotate gradually through all seasons over time, allowing believers across the globe to experience fasting and pilgrimage in varying climates and daylight lengths rather than always in the same season. The Hijri calendar formally begins with the Prophet's migration from Makkah to Madinah, an event chosen by his companions to mark a new starting point for the Muslim community's shared history.

Ask your own question → All questions