Here's Looking at You, Leap Day

On this leap day, we explore fun facts about this quirky date. (For instance, there's a French newspaper that only publishes on leap day!) We also look to the data to explore the various calendars used throughout history.

Have you ever wondered how leap day came about? We have Julius Caesar to thank, according to Wikipedia.

Caesar modified the Roman calendar to form the Julian calendar, which is the calendar as we know it today. And because the astronomical year is about 362.25 days, Caesar’s astromoners added an extra day every four years to account for this gap.

The phrase “leap day” refers to how the day of the week for a given date “leaps” ahead an extra day (rather than simply falling on the next day of the week as it would in a normal year). For example, in 2015, the Fourth of July fell on a Saturday—perfect for BBQs and fireworks! But in 2016, it won't fall on Sunday; instead, it will leap ahead to Monday.

Here are some fun facts about leap day:

  • The French newspaper La Bougie du Sapeur is only published on leap day.
  • In many European countries, women can propose to men on leap day. And if he refuses, he has to buy her 12 pairs of gloves to hide the shame of her ringless finger. (NB: There was a period in English history when Feb. 29 had no legal status.)
  • The Greeks consider it unlucky to marry during a leap year, but especially on Feb. 29 itself.
  • Many countries establish Feb. 28 or March 1 as the official birthday for people born on leap day for purposes of legal coming of age.
  • Anthony, Texas calls itself the "leap year capital of the world." Its festival on Feb. 29 consists of square dancing and “fun at the horse farm.”
  • A one-year prison sentence that spans a leap day means the prisoner has to serve that extra day; the person doesn't get out in 365 days. People working for a fixed annual wage are similarly working for free on this extra day.
  • Leap Day William was made up by 30 Rock, á la Festivus by Seinfeld.

And some leap days are more eventful than others. Here are a few:

  • 1504 – Christopher Columbus predicted the leap day eclipse to con supplies out of Native Americans.
  • 1812 – Sir James Milne Wilson of Tasmania was born.
  • 1880 – Sir James Milne Wilson of Tasmania died at age “17.”
  • 1960 – The first Playboy Club opened.
  • 1976 – Ja Rule was born (yes, the rapper).

All this talk about leap day got me curious about the numerous types of calendars used around the world. So naturally, I visualized the data! Use the viz below to explore the various calendars by astronomical type. You can also click on a calendar name to learn more about its origins.

Happy leap day!