Jalalikalendern
Jalalikalendern, also known as the Jalali calendar or the Persian solar calendar, is a solar calendar used in Iran and Afghanistan. It is one of the most accurate solar calendars in use today. The calendar begins on the vernal equinox, which is the first day of spring, and typically falls on March 21st or 22nd of the Gregorian calendar. The Jalali calendar has 12 months. The first six months have 31 days, the next five months have 30 days, and the last month has 29 or 30 days, with the latter occurring in a leap year. Leap years in the Jalali calendar are determined by a complex astronomical calculation rather than a simple rule like the Gregorian calendar. This precision ensures that the calendar remains closely aligned with the astronomical seasons. The year begins with the month of Farvardin and ends with Esfand. The calendar's origins can be traced back to the Seljuk era, and it was formalized by Omar Khayyam and a group of astronomers in the 11th century. The Jalali calendar is not only a system for tracking time but also deeply embedded in cultural and religious practices in its regions of use, influencing festivals and agricultural cycles.