Leap years, occurring every four years, correct the slight discrepancy between the Earth's orbit and our calendar by adding an extra day to February. Governed by a rule stipulating divisibility by 4, with exceptions for divisibility by 100 but not by 400, leap years maintain synchronization with seasons. This adjustment, introduced by Pope Gregory XIII in 1582, ensures accurate calendrical alignment with celestial phenomena, preserving the harmony between timekeeping and natural cycles.