Feb. 29 is more than just an extra day we have once every four years. There is some science behind it. Here's how leap days came to be.

This year is a leap year, meaning Feb. 29 was added as the 366th day on the calendar. Here's what to know about its meaning, origin, deals and more.

3 A leap year happens when the year can be divided exactly by four (eg 2020 ÷ 4 = 505) – but not if it’s a centennial year (eg 1700, 1900), unless it’s also divisible by 400 (eg 2000)!