Leap Day: 8 Things You Didn't Know

A leap year is every four years and adds one more day to February. But do you know why it happens?

Earth rotates around the sun in 365 days, right?

Close, but it is 365.2422 days ... which is about an extra 6 hours every year. If we didn't add a leap day we would be about 24 hours ahead of schedule to the sun calendar every 4 years. That extra quarter of a day would add 24 days to the calendar over a century, and we'd start to fall out of our seasons, so we "even it out" by adding an extra day every four years to "catch up" to Earth's rotation.

Leap years happen every 4 years, right?

Yes, but it's not that simple. We follow the Gregorian Calendar, which means leap years must follow three rules:

1. The year must be evenly divisible by 4

2. If the year can also be evenly divided by 100, it is not a leap year, unless ...

3. The year is also evenly divisible by 400. Then it is a leap year.

This means 2000 and 2040 are leap years, but 1800, 1900 2100, 2200, and 2300 are not.

Leap years are not a perfect system.

Because a year is 365.2422 days long and not exactly 265.25 days, the math doesn't always add up. We did the math ... we are rounding up and giving the calendar an extra 11 minutes every year, which doesn't seem like a lot, but that's a whole day every 130 years. As a result, certain leap years will be skipped, and those are the ones that are divisible by 100 but NOT by 400, which according to Smithsonian, "the next time a leap year will be skipped is the year 2100."

Fun Facts

1. About 4 million people worldwide have a birthday on February 29th, and the odds of being born on February 29th are 1 in 1,461. Famous people with a birthday of February 29th include motivational speaker Tony Robbins and singer Ja Rule.

2. There is an Irish Legend that St Brigid struck a deal with St Patrick to allow women to propose to men every four years according to Time and Date

3. Leap years align with Presidential elections in the U.S. and the Summer Olympics

4. Julius Caeser is known as the "father of the leap year" starting the tradition in 49 B.C.. Julius Caesar also started the 365-day calendar with the 12 months as we know them now.

So, what are you going to do with your extra 1440 minutes this year?