Leap day, February 29, is a date added to leap years.
A Leap Day, February 29, is added to the calendar during leap years. This extra day, also called Leap Year Day, makes the year 366 days long – not 365 days, like a common year.
Roman general Julius Caesar implemented the first leap day in his Julian Calendar,
I øvrigt lidt sjov at "vores frø" er maskot også for Leapday