The Muslim calendar does not follow the months of January, February and so on. It is linked to the appearance of the new moon, so, when the new moon appears, a new month begins. The most famous month is Ramadan. This year, Ramadan began on the sunset of 5 and sunrise of 6 June. It is always dependent on the sighting of the new moon, and will last until the next new moon is sighted, about 29 days later (5 July). As the calendar is on a lunar cycle, Ramadan is two weeks earlier each year, relative to our calendar (known as the Gregorian or solar calendar).