A leap year is a year that contains one additional day, which in the Gregorian calendar, which is one of the most commonly used calendar in the world, adds one extra day in the month of February after every three years. This means that in a leap year the month of February has 29 days instead of 28 it usually has. The reason behind adding an additional day to the month of February in the Gregorian calendar is to keep the calendar year synchronized with the astronomical or seasonal year.
