Did you ever wonder why there is a Leap Day? What purpose does it serve? Does it really occur every 4 years? These questions along with several fun facts about Leap Day will be discussed in this blog. Articles from Time and Date, History, and Mother Nature Network were used to gather the information below. This week’s sale items can be found using the links at the end of this blog.

Why do Leap Days Exist?

Leap days keep our modern-day Gregorian calendar in alignment with Earth's revolutions around the Sun. It takes Earth approximately 365.242189 days, or 365 days, 5 hours, 48 minutes, and 45 seconds, to circle once around the Sun. This is called a tropical year, and it starts on the March equinox. However, the Gregorian calendar has only 365 days in a year. If we didn't add a leap day on February 29 almost every four years, each calendar year would begin about 6 hours before the Earth completes its revolution around the Sun. This would mean a difference of 24 days every 100 years. Allow this to happen for a while, and Northern Hemisphere dwellers will be celebrating Christmas in the middle of summer in a matter of a few centuries. Leap days fix that error by giving Earth the additional time it needs to complete a full circle around the Sun.

Why Doesn’t Leap Day Occur Exactly Every 4 Years?

Many calendars, including the Hebrew, Chinese and Buddhist calendars, are lunisolar, meaning their dates indicate the position of the Moon as well as the position of Earth relative to the sun. Since there is a natural gap of roughly 11 days between a year as measured by lunar cycles and one measured by the Earth's orbit, such calendars periodically require the addition of extra months, known as intercalary or interstitial months, to keep them on track. There did not seem to be any rhyme or reason to how this was calculated. This ill-defined system irked Julius Caesar and when he became emperor of Rome he re-ordered the Roman calendar. By the 16th century, scholars had noticed that time was still slipping—Caesar's calculation that a year lasted 365.25 days was close, but still overestimated the solar year by 11 minutes. This was a problem for the Catholic Church, as the date of Easter had drifted away from its traditional place, the first Sunday after the first full moon following the vernal equinox, by roughly ten days. Pope Gregory XIII commissioned a modified calendar, one which kept Leap Day but accounted for the inaccuracy by eliminating it on centurial years not divisible by 400 (1700, 1800, and 1900 were not leap years, but 2000 was). The introduction of the Gregorian Calendar marked the last change to the Western calendar as we know it today.

Fun Facts About Leap Day

Leap Day is often associated with marriage, proposals and flipping gender roles. Tradition holds that in 5th-century Ireland, St. Bridget lamented to St. Patrick that women were not allowed to propose marriage to men. So, legend has it that St. Patrick designated the only day that does not occur annually, February 29, as a day on which women would be allowed to propose to men. In some places, Leap Day thus became known as Bachelor's Day. People born on Leap Day are called 'Leaplings.' There are only about 5 million people in the whole world who were born on February 29, with the odds of being born on Leap Day standing at about 1-in-1,461. Several famous people—including actress and singer Dinah Shore (born 1916), motivational speaker Tony Robbins (born 1960) and hip-hop artist Ja Rule (born 1976)—are leaplings. Leaplings technically only get to celebrate their birthdays once every four years, but they do get to be part of an elite group. There's a Leap Year Capital. The twin cities of Anthony, Texas, and Anthony, New Mexico, are the self-proclaimed Leap Year Capital of the World. They hold a four-day leap year festival that includes a huge birthday party for all leap year babies. (ID required.) There's even a leap year club. The Honor Society of Leap Year Day Babies is a club for people born on Feb. 29. More than 11,000 people worldwide are members. The goal of the group is to promote leap day awareness and to help leap day babies get in touch. To see what’s currently on sale at ILA please sign up for our newsletter, view our Facebook page, follow us on Twitter, or visit our website.