🐸📅 A leap year is a calendar year that contains an additional day, February 29th, to keep the calendar year synchronized with the solar year. This extra day helps adjust for the slight discrepancy between the length of a calendar year (365 days) and the time it takes for the Earth to orbit the sun (approximately 365.25 days). Leap years occur every four years, except for years that are divisible by 100 but not by 400.