Leap Year

April 4, 2021


What you may not know about why we add an extra day *nearly* every four years

“Adding an extra day every four years keeps our calendar aligned correctly with the astronomical seasons, since a year according to the Gregorian calendar (365 days) and a year according to Earth’s orbit around the Sun (approximately 365.25 days) are not the exact same length of time. Without this extra day, our calendar and the seasons would gradually get out of sync.”

Old Farmer’s Almanac

The Origins

  • In 46 BC, w/the Egyptian calendar of 365 days falling about 1/4 a day behind the solar year, Julius Caesar ordered 1 day to be added every 4 years.
  • Over the next 1,600+ yrs, the calendar no longer matched the equinoxes.
  • In 1582, the “4 year rule” was amended. Only years equally divisible by 4 are leap years. Centuries (ex: 2000) must *also* be equally divisible by 400 to be leap years.

Leap Day Babies

  • The chance of being born Leap Day (2/29) is 1 in 1,461 because 1,461 is the number of days in four years: 365+365+365+366.
  • At least two women have given birth on three consecutive Leap Days: a Norway mom in the 1900s and a Utah mom in the 2000s.
  • A European family holds the Guinness World Record for the most (three) generations born on 2/29.

LEAPING INTO LOVE? In some European countries, like Ireland, there is a tradition of women proposing to men on Leap Day. Some even consider it to be good luck, but others, like Ukraine and Greece, view Leap Year weddings as bad luck.

Why 2020 Is a Leap Year | When Is the Next Leap Year?

by Jenna Lee,