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Everything You Need to Know About Leap Day


Did you know 2016 is a leap year? 

It is because a leap day will be added to the calendar in February, so February will actually have 29 days this year. This also means that February 29, 2016, is a Leap Day.

The last one occurred four years ago on February 29, 2012.

Why Do Leap Days Exist?

Our calendar is designed to sync up with the Earth’s revolutions around the sun. More specifically, it takes our planet approximately 365.242189 days – 365 days, 5 hours, 48 minutes, and 45 seconds – to circle one time around the sun. This is why we have 365 days in our calendar.

The full rotation – decimals included – is called a tropical year. It’s also known as a solar year, astronomical year, or an equinoctial year.

The problem is that those extra hours, minutes, and seconds – the ones that are part of the decimal on the end of the tropical year – add up over time. If we didn’t include a leap day every four years, we would lose nearly six hours each year. It would add up to a total of 24 days in a span of 100 years. Over time, our calendar wouldn’t match up correctly and things would get a little weird.

So, we introduce a leap day every four years to keep our calendar in alignment with the Earth’s revolution around the sun.

After more precise calculations, a marginal difference of 0.000125 days exists between the Gregorian calendar average year and the solar year. So, in 8,000 years, the calendar will be almost one full day behind. However, at that time, the length of the vernal equinox will have changed also, by an amount that cannot be predicted. Therefore, the current Gregorian calendar suffices for practical purposes and is the most accurate method for determining our relation to the Earth’s revolution around the sun.

Interestingly enough, the Chinese calendar added a month in 2015 – which was a leap year in their calendar – as opposed to the Gregorian calendar, which calls for a leap day to be added this year (2016). Under the Chinese leap year an additional month is tacked onto the year, but where it is added varies. The added month always carries the same name as the month that preceded it.

We created an infographic that highlights 20 cool facts about Leap Day. Check that out here!

Where Did the Concept of Leap Days and Years Come from?

The ancient Roman calendar added an entire month every few years instead of adding a single day here and there. For the Romans, this kept the calendar in line with seasonal changes, and was a remarkably similar practice to the Chinese leap month; which is how the Chinese handle the time sync.

Believe it or not, the Roman General Julius Caesar was the first to introduce a leap day in 45 BCE (Before Common Era) to the calendar at the time, which was actually called the Julian Calendar.

Like we do now, he had a leap day added to the calendar every four years. However, the leap day occurred on February 24, instead of the 29. In addition, February was actually the last month of the calendar, so Caesar added the leap day to the end of the year.

This improved things slightly, yet leap days were being added too often. This is why Pope Gregory XIII popularized the Gregorian Calendar, in 1582. It is the same calendar we use to this day, and it introduced a much more accurate method for dealing with leap years, although, at the time, leap years were referred to as bissextile years or intercalary years.

How Many Leap Days Have There Been?

Since the concept of a leap day was established between 46 and 44 BC by Julius Caesar and the original method was discontinued by Pope Gregory XIII in 1582 there were a total of nearly 407 to 408 leap days.

Between 1582 and 2016 there have been another 108 or 109 leap days. This is because the years 1700, 1800, and 1900 were not considered leap years.

Exceptions exist to the rule that a leap year happens every four years since the true duration of a solar year is slightly less than 365.25 days. Years that are evenly divisible by 100 are not considered leap years unless they are also evenly divisible by 400, in which case they are leap years. This is why the years 1600 and 2000 were leap years, but 1700, 1800 and 1900 were not.

Similarly, the years 2100, 2200, 2300, 2500, 2600, 2700, 2900 and 3000, in the future, will not be leap years, but 2400 and 2800 will be.

Altogether, there have been a total of 515 to 517 leap days from its creation in 45 BC and today. But this is not completely accurate because of the shift made by Pope Gregory XIII, and because not every nation that existed at the time adopted the modern dating system.

Interesting Leap Day Traditions

Due to the nature of leap day, it has been associated with a variety of ancient customs, folklore, superstitions, and traditions.

One common tradition – which has been around for quite some time – is that women actually propose to their boyfriends, instead of the other way around. This is not as impactful today as it used to be in the past, thanks to the dissolution of gender roles.

Celebrities Born on Leap Day

A person born on leap day – February 29 – is actually given a special name; they are called a “leapling” or “leap-year-baby”. Being born on a leap day makes celebrating birthdays especially difficult since the day only exists every few years. Therefore, leaplings most often celebrate their birthdays either on February 28, or March 1, during non-leap years. There are a select few who choose to only observe their birthdays on the authentic day, February 29 which comes every intercalary year.

The legal birth date for leaplings varies depending on the country and region where they are born. The Honor Society of Leap Year Day Babies estimates there are currently 4 million leaplings out there.

Some famous celebrities that have been born on a leap day are:

  • Ja Rule (Jeffery Atkins) – Leap Day Age is 10, Real Age is 40
  • Antonio Sabato Jr. - Leap Day Age is 11, Real Age is 44
  • Tony Robbins - Leap Day Age is 14, Real Age is 56
  • Claudia Williams - Leap Day Age is 5, Real Age is 20
  • Simon Gagne - Leap Day Age is 9, Real Age is 36
  • Caitlin EJ Meyer - Leap Day Age is 6, Real Age is 24
  • Majesty Rose - Leap Day Age is 6, Real Age is 24
  • Saul Williams - Leap Day Age is 11, Real Age is 44
  • Dennis Farina - Leap Day Age is 18, Real Age is 72
  • Billy Turner - Leap Day Age is 19, Real Age is 76

You can find a complete list of celebrities with Leap Day birthdays on Wikipedia.

Interesting Fact: There is a 1 in 1,461 chance of having a birthday on February 29 or a leap day.

The Leap Day in History

Several historic events have happened on Leap Day throughout the years. Here is a timeline featuring some of the most interesting ones.

1504 – Christopher Columbus convinced a Native American tribe to give him supplies by using his knowledge of a lunar eclipse that happening during the evening on the leap day of this year.

1644 – Abel Tasman, a Dutch explorer, began his second Pacific voyage.

1704 – During the Queen Anne’s War, French forces teamed up with Native Americans to stage a raid on the settlement of Deerfield, Massachusetts. In the attack, 56 villagers died and over 100 were captured and became imprisoned.

1796 – The Jay Treaty calls for peace between the United States and Great Britain, and also establishes peaceful trading operations.

1864 – During the American Civil War, Kilpatrick-Dahlgren mounts a raid on a strategic position near Richmond, Virginia where more than 15,000 Union soldiers are being held captive. His attack fails.

1892 – St. Petersburg, Florida is incorporated as a town. It would later be re-incorporated as a city on June 6, 1903.

1912 – The Piedra Movediza located in Tandil, Argentina fell and broke. It was a 300-ton rock that balanced – more like teetered – on the edge of a steep hill. It was also called the “Moving Stone” because it would rock in an extremely slow manner without falling.

1916 – Tokelau in New Zealand was annexed by the United Kingdom.

1916 – Child labor laws in South Carolina were changed to meet modern standards. The minimum working age for factory, mill, and mine employees was increased from twelve to fourteen years old. Sorry folks, no more twelve-year-olds working on the mines!

1936 – The February 26 Incident, a coup d'état started in Tokyo by young Imperial Japanese Army (IJA) officers, ended.

1940 – Hattie McDaniel became the first African-American in history to win an Academy Award for her role as Mammy in Gone with the Wind.

1944: During World War II, American General Douglas MacArthur invades the Admiralty Islands under Operation Brewer.

1960 – A 5.7 magnitude earthquake on the Richter scale rocked Agadir in coastal Morocco. The perceived intensity of the quake is X (Extreme) which is the third highest intensity level, behind XI (Extreme) and XII (Extreme). The quake decimated Agadir and caused a death toll of between 12,000 and 15,000 (a third of the city’s population), with another 12,000 injured and well over 35,000 people left homeless.

1964 – Australian swimmer Dawn Fraser sets a new world record in the 100-meter freestyle swimming competition, which was being held in Sydney. Her time was 58.9 seconds, one of the fastest ever recorded.

1972 – During the Vietnam War, South Korea withdraws about 11,000 troops out of its total 48,000 deployed in Vietnam. This was part of a policy enacted by the Richard Nixon administration to end U.S. involvement in the Vietnam War, called Vietnamization.

1980 – Gordie Howe scores his 800th goal in the NHL for the Hartford Whalers, setting a league record and making history.

1988 – Svend Robinson, a member of the Canadian House of Commons, comes out as gay. This is significant because he was one of the first members in history to do so.

1992 – This leap day marked the first day of Bosnia and Herzegovina’s independence referendum, which saw them break off from Yugoslavia and become independent states.

1996 – Faucett Flight 251 tragically crashes into the Andes, resulting in the deaths of all 123 passengers and crew (117 were passengers). The aircraft was a Boeing 737-222, and it crashed because the crew had been issued an out of date barometric altimeter setting, which meant that they were actually flying 1,000 feet lower than readings showed they were at. This led them to crash in the hills, just 2 kilometers shy of the airport runway where they were supposed to land.

2000 – During the Second Chechen War, a Russian VDV paratroop company was attacked by rebel Chechen and Arab fighters, during an attack on a guard post near Ulus-Kert village. An estimated 84 Russian soldiers were killed during the fight.

2004 – Haiti’s President, Jean-Bertrand Aristide was ousted during a coup d'état following several weeks of conflict. One of his close former soldiers participated in the coup against him. He was forced to leave Haiti on a U.S. plane while being escorted by U.S. military and security personnel, to ensure his safety. He has since claimed that the U.S. is responsible for orchestrating the coup, and kidnapping him. As a result, Aristide was exiled from Haiti and now resides in South Africa.

2008 – The UK Ministry of Defence withdrew Prince Harry from his tour in Afghanistan “immediately” because the Australian media (a magazine) leaked information about his deployment. The Ministry feared for his safety considering Harry is a person of high importance. Until his removal, Harry had served for 77 days in Helmand, Afghanistan. He later deployed to Afghanistan once again for a period of 20 weeks with the Army Air Corps.

2008 – Misha Defonseca, a renowned Belgian writer, admitted that her book – previously thought to be an autobiographical memoir – was fictitious. First published in 1997, Misha: A Mémoire of the Holocaust Years told the story of how she survived the Holocaust, by living in the woods with a pack of wolves. She only admitted the hoax – through her lawyers – after a Belgian newspaper approached her with “irrefutable” evidence that her story was falsified. As a result, in 2014, she was ordered to pay her publisher $22 million in damages.

2012 – Construction of the Tokyo Skytree is completed. It is the tallest tower in the world – replacing Canton Tower - at 634 meters high, and the second tallest man-made structure on the planet, second only to the Burj Khalifa. The Skytree operates as a broadcasting and observation tower, and there’s also a restaurant inside. Construction began on July 14, 2008, and wrapped up on February 29, 2012, a total of 1,325 days or 3 years, 7 months and 15 days.


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