Every four years, an additional day is added to the month of February, which makes 29 February is a Leap Year.
However, 2023 is not a Leap Year, as this year February ends on Tuesday 28.
The Gregorian calendar usually has 365 days, but in a Leap Year, it has 366 days.
This once-every-four-years calendar event is important to ensure our calendar year matches the solar year, which refers to the amount of time it takes for the Earth to make a trip around the Sun.
The last Leap Year took place in 2020, which means the next one will be in 2024.
Here is everything you need to know about Leap Years and why they are important.
What is a Leap Year?
A Leap Year occurs when one extra day is added to the Gregorian calendar, which means that the year has 366 days instead of the usual 365.
It takes approximately 365 days for the Earth to orbit the Sun, but this is a rounded-down figure. In more accurate terms, it takes closer to 365.25 days for the Earth to make its full journey around the Sun.
According to NASA, this means that there is a “leftover piece of a day” that needs to be accounted for. To ensure this extra time is counted, one day is added to the calendar every four years.
Why is the extra day important?
The function of Leap Years is to ensure that the calendar year matches the solar year.
It might seem like subtracting almost six hours off a year is insignificant, but as the years go by, that additional time could wind up causing problems.
“For example, say that July is a warm, summer month where you live,” NASA explains. “If we never had leap years, all those missing hours would add up into days, weeks and even months. Eventually, in a few hundred years, July would actually take place in the cold winter months!”
However, there are some exceptions to the rule of a Leap Year every four years.
James Evans, a physicist at the University of Puget Sound, told the National Geographic magazine: “As it turns out, if you stick in one [day] every four years, that’s a few too many.”
This means that Leap Years fall on every year that is divisible by four, except for years that are exactly divisible by 100.
However, years that are divisible by 100 are still Leap Years if they are exactly divisible by 400. For example, the years 1600 and 2000 were still Leap Years, while the years 1700 and 1900 were not.
What is Leap Day?
Leap Day falls on 29 February.
The first Leap Day was introduced by Julius Caesar on the Julian Calendar, which was established in 45 BC. It came after Roman Emperor Augustus, who began his rule in 27 BC, is believed to have wanted his dedicated month to have the same number of days as the month named after Julius Caesar.
At the time, historians say the month of February had 30 days, while the month of August had 29. Meanwhile, the month of July had 31 days.
It has been theorised that the emperor decided to remove two days from February to be added onto August, making August a 31-day month and February a 28-day one.
Historians also think that February became the chosen month for Leap Day because the Romans didn’t much care for the month and saw it as a “leftover month that nobody really wanted to begin with”.
Ben Gold, a professor of astronomy and physics at Hamline University, said: “They had winter, a long period of winter, which they didn’t really like very much and didn’t even want to put it in months.”
A person who is born on 29 February can be referred to as a “Leap Year baby”, a “leaper” or a “leapling”.
Notable figures who share that unique birthday include rapper Ja Rule, motivational speaker Tony Robbins, Mark Foster, frontman of Foster the People, US actor and singer Dinah Shore, and French actor Michele Morgan.
