How is a leap year formed?

Explanation

Actually, the Earth takes 365 days to revolve around the Sun. It means 6 hours excess in every year and these 6 hours makes 1 day in 4 years. After every 4 years, 1 day is added in the month of February. Thus, every fourth year, February is of 29 days instead of 28 days. Such a year with 366 days is called a leap year.