Leap day is a day added to the end of February approximately every four years to keep the calendar consistent.
The exact time it takes for the Earth to revolve around the Sun is 365.2422 days. Ancient calendars had only 365 days; the extra quarter of a day gradually shifts the calendar with each year, which means that the seasons wouldn’t be in the same months each year.
To fix this issue, scientists have attempted to add a day to the calendar. The Julian calendar was the first to propose a leap day every four years, but an error in measurement left the issue unresolved.
The Gregorian calendar, issued by Pope Gregory XIII, reformed the Julian concept by eliminating leap years in centuries not divisible by 400. The official rule, according to the United States Naval Observatory, is as follows:
“Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is.”
People born on Feb. 29 are called leaplings. The probability of being born on a leap day is one in 1461 — meaning only around 4.8 million people in the world are leaplings.
Different cultures have different superstitions associated with Feb. 29. In Greece, tradition says it is unlucky to get married during a leap year.
However, Irish tradition states women are only allowed to propose during leap years; if the man refuses, various cultures have humorous — and expensive — consequences.
According to legend, Queen Margaret of Scotland required compensation for a rejected proposal to be a pair of leather gloves, a single rose, £1 and a kiss. Finland’s tradition is for the man to buy the woman materials for a skirt.
Modernly, the Irish tradition is limited just to proposals on Feb. 29; in pop culture the tradition is explored in the romantic comedy “Leap Year.”
In France, a satirical print publication called La Bougie du Sapeur is published once every four years on leap day.
Additionally, there is a small town in Texas called Anthony that has declared itself the “leap capitol of the world.” The town hosts a Worldwide Leap Year Festival every leap day to celebrate leaplings.
