So NASA, Tell Us… Why Does Leap Day Exist?

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Today is February 29th, or “leap day,” which means that an extra day has been added to the month resulting in a “leap year.” This curious calendar occurrence, which happens once every four years, is connected with everything from ancient folklore – the only time women had the “right” to propose to men, dating back to 5th century Ireland or 1288 Scotland and a declaration made by then 5-year-old Queen Margaret, to superstition – freakish weather patterns, babies born (a.k.a. Leaplings or Leapers) either unlucky/difficult or with unusual talents. But we wanted to get down to the nitty gritty… we wanted the scientific scoop.

So here’s the answer to our “why” as explained by NASA

“The reason for adding leap days to the calendar is to align the calendar year with the actual year – which is defined by the time it takes Earth to circle the sun. It is equal to 365 days, 5 hours, 48 minutes and 46 seconds, or 365.24219 days.


If all calendar years contained exactly 365 days, they would drift from the actual year by about 1 day every 4 years. Eventually, July would occur during the northern hemisphere winter! Wouldn’t that be weird?

To correct (approximately), we add 1 day every 4 years…resulting in a leap year.

By making most years 365 days but every fourth year 366 days, the calendar year and the actual year remain more nearly in step.”