Rumi calendar is a special type of calendar that is used by followers of the Islamic faith. It is different from the regular Western calendar, which is based on the solar cycle and the changing of seasons. The Rumi calendar is based on the lunar month, which is the time it takes for the moon to make one complete cycle around the Earth. Each month in the Rumi calendar is 29 or 30 days long, meaning that a year in the Rumi calendar is shorter than a year in the Western calendar. People who use the Rumi calendar must look for the first new crescent moon in the sky each month in order to know when the new month is starting.