Most people know that a leap year is every four years and that it has something to do with the Earth circling the sun. But many may not be aware of the purpose of this extra day – and may know even less about how it came to be. The story is complex and it goes back to ancient Roman times. Over the centuries, February 29 has prompted some unusual customs, wild rumors and strange superstitions.
A year is actually longer than 365 days
It's all about the sun! We grew up being told the Earth takes 365 days to make a complete circle around the Sun, but it actually takes 365 days, 5 hours, 48 minutes and 45 seconds – or 365.24219 days. An extra day is added about every four years as a corrective measure to stay in sync with the solar year.
There used to be a whole leap month
Ancient Romans had an extra month every few years because the Roman calendar year was 355 days – 10 days and a few hours shorter than the solar year. To fix that issue and to keep the calendar in sync with the change of seasons, the Romans added an extra month every few years. After a while, this method was too chaotic. That's why Julius Caesar and astronomers decided to add just one day on a more consistent basis – every four years. Caesar is known as "the father of the leap year."
There was a February 30 at one point
February had 30 days at least on two occasions. Sweden wanted to switch from the Julian calendar to the Gregorian calendar in 1700. But 1700, which was supposed to be a leap year in the Julian calendar, ended up being a regular year in the country. The error led to more mistakes and a lot of confusion. Sweden had to go back to the Julian calendar and added two leap days in 1712 to get back in line. The country eventually converted to the Gregorian calendar in 1753.
February 30 was an actual date in the Soviet Union in 1930 and 1931. Officials wanted to even out the year and have five-day weeks and 30-day months. This, too, created a lot of confusion and the seven-day week was restored in 1940.
Leap years are not always every four years
Determining a leap year seems pretty straight forward – every four years. But every rule has exceptions. A leap year has to be exactly divided by 4, but cannot be divided by 100 – and this is why 2100 or 2200 will not be leap years. But this exception also has an exception: If the year is divisible by 100, and also divisible by 400, then it is a leap year – just like the year 2000 was.
There have been just over 100 leap days
The Julian calendar, according to which a year was 365 days and six hours – 11 more minutes than the actual length – was suspended in 1582 by Pope Gregory XIII. Since 1582 there have been 108 or 109 leap days – not that many for a tradition that has been around for five centuries.
However, if you include the leap days established with the Julian calendar around 45 BC, then there have been a total of 515 to 517 leap days.
The chances of being a leapling are tiny
The chances of being born on any day are 1 in 365. Multiply that by four, and the odds of being a leapling are 1 in 1,461. So, statistically speaking, if birthdays are evenly distributed throughout the year, 0.07% of the world's population was born on a leap day.
There is a club for people born on leap day
Leaplings have their own club, and membership is free. The Honor Society of Leap Year Day Babies, which dates back to 1988, also offers a birth family search service. The club will publish information about someone who may be born on Feb. 29 to help with finding them.
There is a tradition that women propose marriage on leap day
While the cultural norm is for men to propose marriage to women, the roles are reversed on a leap day, according to the custom that is rumored to have started in 5th-century Ireland. The story goes that St. Brigit of Kildare complained to St. Patrick that women had to wait for men to pop the question. As a result, he declared that women can make an offer of marriage on a leap day.
Men had to accept the proposal or pay a fine
According to tradition, a woman's proposal on leap day was an offer a man could not refuse. If he did, it would cost him 12 pairs of gloves. The woman needed the gloves to hide her shame at not having an engagement ring on her finger. Another type of "fine" for declining was a silk dress as consolation.
Feb. 29 can't be used on some official documents
Some businesses and organizations have left the date of Feb. 29 out when digitizing their registration processes. Many leaplings still have problems when asked to enter their birth date. Applying for a driver's license can be frustrating, as some states don't let you put February 29 as the date of birth. Some states have statutes specifying whether February 28 or March 1 is to be used; if they don't, the default date is March 1.
There are three generations of leaplings in one family
There has been only one confirmed case of a single family having kids in three consecutive generations born on leap day. Peter Anthony Keogh was born in 1940 in Ireland; his son Peter Eric was born in 1964; and his granddaughter Bethany Wealth was born in 1996.
You may be working for free on leap day
Full-time employees with a fixed annual salary who work on February 29 may actually be working for free. An annual salary is technically set for a typical year, which doesn't include the extra day every four years. This is not an issue when people are paid by the hour.
There is a Leap Capital of the world
Leap year has a hometown and it's Anthony, Texas, which is on the border with New Mexico. Every leap year it hosts the Worldwide Leap Year Festival, which features parades and hot-air balloon rides.