Iran has a special calendar that is different from most other countries. The Iran calendar is made up of 12 months which are all between 29 and 32 days long. The months are named with Farsi names and start at the beginning of spring. The year starts at the time of the vernal equinox, which is the first day of spring when the days and nights are equal in length. In addition to the 12 months of the year, the Iranian calendar also adds an extra month every few years to keep their calendar in line with the seasons. This extra month is known as a leap month.