As you may know, 20-20 is a leap year.

Every four years, february 29th is added to our calendars.

There really is only "one" reason we have leap years.

It deals with the earth's orbit around the sun.

Storm team 10's david siple explains.

Every four years we add an extra day to the calendar.

Well why exactly is that?

Let's take a look at our solar system.

Just the earth and the sun.

As you know, the earth orbits the sun once a year.

That's every 365 days.

Well technically it takes 365 days and roughly 6 hours to completely orbit the sun so really we don't orbit the sun exactly for 365 days.

To help us visually see this, let's take a bird's eye view of the solar system.

When the earth travels around the sun for a year, exactly 365 days, 6 hours of that orbit is not included in our calendar during a non-leap year.

The second non leap year, essentially a half of a day is not yet compensated for..

Three years around the sun we have, you guessed it, 18 hours of a day that are not made up for in the calendar.

Now every 4th year, a leap year, our calendars show an extra day, february 29th, to compensate for an entire day that the earth made from traveling around the sun in 4 years.

What if we didn't do this?

Well, nasa says that if we went 100 years without having leap days every 4 years, summer would not begin until late july.

And winter wouldn't begin until late january.

500 years without leap days, well summer would not show up until the calendar says december.

In the wthi studios, i'm storm team 10's david siple.

Back to you.