Designer & bike rider in British Columbia, Canada

Leap Year Rules

Today is a very special day. The year is now one day longer. A lot of 100-year-old people are actually celebrating their 25th b-day (see below). Kids born today are falling into the same time bubble. Today should be a global holiday.


It is a unique day, added rationally yet sort of anomalously to regular old time. Today should encourage people to perform acts outside their usual habits, with no repercussions. A day quickly enjoyed and immediately forgotten. “Hey, it was a leap year, forget about it” being the proper attitude.
Our current base-6 time system is of course a human and arbitrary construct, yet so important and culturally programmed to be as real as our loop around the Sun, as if every second were born, alive, then ticked away. That February 29 really is a sort of temporal anomaly. In fact, there are strict rules dating back hundreds of years to when ol’ Pope Gregory XIII intro’d the calendar (aptly named the Gregorian) in 1582 to govern Feb. 29’s occurrence.
The three-part condition for a leap year (culled from the Canadian Institute for National Measurement Standards):
1. If divisible evenly by 4, a Gregorian year is a leap year, with a February 29 and 366 days (e.g. 1996/4 = 499, so 1996 is a leap year), UNLESS
2. If divisible evenly by 100, a Gregorian year is a normal year with 365 days (e.g.1900/100=19, so 1900 is a normal year of 365 days; as is 2100), UNLESS
3. If divisible evenly by 400, a Gregorian year is a leap year; so the year 2000 is a leap year.
So that 100 year old having his/her b-day today has technically celebrated Feb. 29 how many times? Born in 1904, he/she would have celebrated a max number of 25, plus the first year of course, so 26 (Rule One, 100/4). But hey, you don’t count your birth as your first birthday, so it’s now 25 times this old-timer has celebrated. Except minus the year 2000 (Rule 2) so now 24, but wait 2000 was a leap year because of Rule 3, so the final tally is 25. But now take a really well preserved person, born say Feb. 29, 1896. 1900 was not a leap year (Rule 2), so for being 8 years older then our Centurion, he’s only snuffed the candles one more time, 26. Am consulting some more mathematically-minded friends of mine and see if we can come up with a smart-looking equation for all this.
Hmm. I just noticed my watch couldn’t care less about the Pope and has skipped directly to March 1.


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Comments

One response to “Leap Year Rules”

  1. Graham Avatar
    Graham

    I think that this equation might do the trick.
    b := birth year (a valid leapyear)
    c := current year (also valid leapyear)
    int() := round down to nearest integer
    birthdays = (b-c)/4 – int(c/100) + int(b/100) + int(c/400) – int(b/400)

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