ENTITY reports on what is a leap year.Photo via Shutterstock

Do you ever hear people talking about leap years but have no clue how it even started? Yeah same here.

Because we’re just as confused as you are, we decided to find some answers. What is a leap year, you ask? Here’s what we know.

So next time someone talks about leap years, you’ll actually be able to join their conversation.

What is a leap year?

ENTITY reports on what is a leap year.


A common year usually has 365 days, but every four years we have a leap year, which has 366 days. The extra day gets added to the shortest month on the calendar, February. So instead of ending on February 28, the month goes up to February 29 on leap year.

And though it may seem like a pointless addition to our year, a leap year is actually very important because it keeps the calendar year equal to the astronomical and seasonal years.

The name “leap year” came from the fact that every four years, a day normally advances and skips a day of the week from one year to the next. To make it more simple, let’s look at Christmas. December 25, Christmas Day, fell on a Tuesday in 2001, Wednesday in 2002 and Thursday in 2003. But in 2004, it “leapt” over Friday and fell on a Saturday.

Who created the leap year anyway?

ENTITY reports on what is a leap year.


The Julian calendar was introduced by Julius Caesar, which standardized the 365-day year and created the guidelines similar to our current leap year. This calendar was introduced in 46 B.C. but was reformed by Pope Gregory XIII in 1582.

The Gregorian calendar is now used as the main calendar throughout the world, but it was originally based on the Julian calendar. And the Julian calendar inserted a day every four years to get in line with the solar year.

The problem with the Julian calendar, however, is that it was too long – 11 minutes and 14 seconds too long, to be exact. His calendar was averaging 365.25 days a year, but the length of the solar year is actually 365.242216 days.

This may not seem like a lot, but over the course of centuries, it added up. Thus, Pope Gregory XIII adjusted the calendar by moving the date ahead by 11 days and by creating the leap year rule.

The Gregorian calendar also follows strict rules to determine which years are leap years. If the year can be divided by four it is a leap year, but if it can be evenly divided by 100, then it is not … unless it can be divided by 100 and 400. So, the century years 1600 and 2000 are leap years, but 1700, 1800 and 1900 aren’t.

Why do we have leap years?

ENTITY reports on what is a leap year.


We have leap years because the seasons and astronomical events don’t repeat in whole numbers. In a solar year, the length of time it takes the Earth to travel around the sun is 365.25 days. We have a leap year every four years so that it can catch up to the solar year.

Overall, it’s really important to have a leap year so our calendars don’t get mixed up. And now that you’re a leap year expert, you can let everyone know the next leap year will occur in 2020.


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