We calculate our year by the time it takes the earth to make one full orbit around the sun, which we typically assume is 365 days. However, it actually takes the earth approximately 365 days, 5 hours, 48 minutes, and 56 seconds to make this trip. Therefore, to correct our calendar year, we take this extra time and put it together, adding a leap year every 4 years.

Leap years do not always occur every 4 years, because adding up the extra time does not equal an even 24 hours (aka a full day). So to correct this centuries do not always count for leap years. In order for a century to be a leap year, it must be divisible by 400 instead of 4. For example, the year 2000 was a leap year, but the year 2100 will not be.

Now that we understand leap years, we can learn a brief history of them. Leap years were implemented by Julius Caesar in 46 B.C. In 1582, Pope Gregory XIII corrected the errors in Julius Caesar’s calculations by implementing the Gregorian Calendar creating the system that we are familiar with in present time (adding in the century rule to leap years).

Lastly, here are a few fun leap day facts!

1. People born on leap days are called “leapers” or “leaplings”

2. Chances of being born today, February 29, are 1/1461

3. There is a club called, “The Honor Society of Leap Year Day Babies,” exclusively for people born on February 29th. They currently have 11,000 members

4. The animal most commonly associated with a Leap Year is a frog