سی‌ام (30th) is a Persian term that refers to the thirtieth day of a month in the Iranian calendar. This calendar is a solar calendar, meaning it is based on the Earth's revolutions around the Sun. Each month typically has 30 days, making the 30th day significant as it marks the end of the month. In the context of celebrations, the سی‌ام of certain months may coincide with important events or holidays in Iranian culture. For example, the last day of Farvardin, the first month of the year, is often associated with the celebration of Nowruz, the Persian New Year.