TRCF Featured Intern Post

The Leap Year

By TRCF intern Natalia Mitsui

Calendars carry the extra weight of an additional day in February this year.  A leapling or leaper, a person with a birthday on Feb. 29, born in 1912 will have only celebrated 25 legitimate birthdays. Granted, a 21 year old that technically only has had five legitimate birthdays is not barred from drinking, but the legality of the birthday is not entirely clear. Since a person’s age is figured by years and not by the actual day, a person born on a leap day is legally whatever age they turn that year on March 1.

So why is there an extra day added every four years?

The leap year was started in B.C. 45 by Julius Caesar when he consulted astronomer Sosigenes of Alexandria to simplify the calendar. Before the Julian calendar was adopted, a more complicated Roman calendar was used. The Roman calendar had the usual twelve months, but there were days that were missing from how we know it today. The year totaled to 355 days, 10 days shy of the Julian calendar. With the missing 10 days the calendar had a tendency to shift from the solar year, also known as the tropical year or the amount of time it takes for the Sun to return to the same position in relation to the Earth. To compensate for this shortage of days, a 13th month was inserted between February and March. The consistency of this extra month, called Mercedonius or Intercalaris, was not clear and people living outside of Rome were never clear as to what day it was.

The introduction of the Julian calendar introduced the months as they are currently counted, along with the addition of the extra day in February. According to Sosigenus the solar year was not precisely 365 days, but 365.25 days. Since a quarter of a day could not be added, a day was intercalated every four years instead. If a leap year was not added the calendar would diverge 25 days every 100 years, meaning that summer would start in the middle of July instead of June and progressively get pushed further and further back.

However, this calculation was not entirely correct either. In 1582 the introduction of the Gregorian calendar (the one currently being used) was introduced by its namesake Pope Gregory XIII. A solar year was not 365.25 days, but actually 365.242 days –or 365 days 5 hours 48 minutes 46 seconds. Although the 11 minutes 14 seconds difference may seem like nitpicking, there is a logical reason why the calendar needed to be adjusted. For every 400 years, three days would be added; which may not seem like much, but in the span of history this makes a difference. To fix this the Gregorian calendar kept the leap year, but added the addendum that any year divisible by 100 would not be a leap year unless it was divisible by 400. By doing this, three leap days were eliminated every four hundred years, removing the additional days the Julian calendar counted. This means that although 2000 was a leap year, 2100 will not be. At the current rate, it will be 3,300 years before the calendar shifts deviates the solar year.

Whether it is the rareness of the day or something else, leap day has inspired some unique traditions, superstitions, and events.

There is an Irish tradition dating back to A.D. 500 called “The Ladies’ Privilege,” where a woman is allowed to propose marriage to a man on leap day. Some have extended this to the entire year, but this was a response to the old tradition that only a man may propose. Refusing a proposal from a woman required compensation by the man in the form of cash, a gown, or even a kiss. This antiquated tradition that would offend a modern day feminist was depicted in a lackluster Amy Adams romantic comedy, Leap Year.

On the other hand, in Scotland being born on a leap day and getting married in a leap year is considered unlucky. The Scots also have the saying, “Leap year was never a good sheep year.” Along with the thought that beans and peas planted in a leap year “grow the wrong way” and leaplings are hard to raise and likely to be sickly. The day seeped in superstition stems from the fact that many people previously thought that the additional day was unnatural and could potentially knock nature off its balance.

Some modern day events include The Worldwide Leap Year Festival that takes place in Anthony, Texas/New Mexico –the self proclaimed “Leap Year Capital of the World.” The event was started in 1988 by Mary Ann Brown, a leapling born in 1932, to promote her town and celebrate leap day born people.

On a different note, Rare Disease Day was first observed on Feb. 29, 2008. Rare Disease Day is an international grassroots advocacy day aimed at bringing awareness and recognition of rare diseases as a global health challenge. According the Orphan Drug Act of 1983, a disease is considered rare if it affects less than 200,000 people. There are nearly 7,000 known rare diseases affecting approximately 30 million American –which works out to 1 in every 10 Americans. The holiday was specifically held for the first time on a leap day, as it was considered a “rare day.” During a common year (a non-leap year), Rare Disease Day is held on Feb. 28. This year will be second year when the holiday will be observed on the day it was originally intended, with the theme of solidarity: “Rare but Strong Together.”

The draw of leap day lies in its infrequency. Coincidentally, the summer Olympics and the U.S. Presidential election also fall on a leap year. However, the true oddity of the day comes from the name. Why is it called leap day? A day is being added to the calendar, not being leapt over. If anything it would make more sense to call all other years a leap year as it “leaps over” the 29th.

There are two theories as to the origin of the name. One theory is that a leap day causes fixed festival holidays, which usually advance by one day in the week per year, to “leap” ahead one weekday. The other theory is that it originated in England when the British government previously did not officially recognize Feb. 29 as a day with any legal status. This would mean that no decisions or contracts made on this day would be legally binding. To solve this problem the British “leapt over” the 29th as it did not legitimately exist, thus giving the extra day its name.

For more information on Rare Disease Day visit and

For more information on The Worldwide Leap Year Festival visit

TRCF intern blog posts are written to give a local as well as global perspective on the seven issue areas that TRCF funds. We welcome your input and thoughts on these posts on our Facebook page. If you have a topic that you would like one of our interns to write about please contact us through the website with your suggestions.