2024 is a leap year, with a day that only appears on the calendar every four years.
Here’s why we do this.
The Earth takes 365.24219 days to travel around the sun.
That extra .24219 days may seem small, but since calendars only have 365 days.
That means that every year we get just a little knocked off the timing of the seasons, by about six hours every year.
So to prevent Halloween from happening in the middle of winter, we add a leap day every four years.
This allows farmers to set regular days for sowing the fields and harvesting the crops, and it helps everyone else have regular seasons.
For those born on a leap year, many just celebrate it every year on Feb. 28 or April 1.
We have Julius Caesar and his Julian calendar to thank for the leap day starting in 45 BC.
But even with the addition of leap years, the calendar still isn’t perfectly aligned with the Earth’s orbit around the sun.
In 1582, people began to notice that the calendar was off by 10 days.
That’s when Pope Gregory XIII established the Gregorian calendar and deleted three leap days every 400 years.
That’s why there was no leap day in 1700, 1800, and 1900, but there was one in 2000.
And there won’t be one in 2100.