FYI: History of the Leap Year

Editor’s note: This is part of an ongoing series that explores stories through data.

Most of us know there’s a Leap Year every four years. But do you know how it came to be?

2016 has 366 days instead of the typical 365 because the modern Gregorian calendar, the most widely used calendar in the world, needs to stay in sync with the Earth’s revolution around the sun-which takes 365.2 days. This is also known as a tropical Year. The Gregorian calendar has only 365 days, making it a quarter of a day short of the full tropical year.

The purpose of the Leap Year is to compensate for the Gregorian calendar.

Learn more about the history of the Leap Year:

Planning AheadInfographic