It only happens once every 4 years, except for years ending in 00, in which case only if the year is divisible by 400. So we had one in 2000.
I always wondered how people feel that were born on Leap Day who only get to have a birthday every 4 years. They call these people leapers. I guess it’s a way to stay young. There is even a book called “Leap Day” by Wendy Maas.
Why do we have it anyways? The Royal Greenwich Observatory says:
“Our solar year (the time required for Earth to travel once around the Sun) is 365.24219 days. Our calendar year is either 365 days in non leap years or 366 days in leap years (Feb 29th inserted). A leap year every 4 years gives us 365.25 days, sending our seasons off course and eventually in the wrong months.
To change .25 days to .24219, we need to skip a few leap days (Feb 29ths) …. century marks not divisible by 400. So with a few calculations tweek the calendar by skipping 3 of 4 century leap years to average out our calendar year to 365.2425, which is pretty darn close to the solar year 365.24219. ”
Got it? Somemore interesting history of Leap Year is at Leaper John Strohsacker’s web site.
