This Monday February 29 is a leap day, the rarity of the calendar that occurs (almost) every four years. For centuries, trying to synchronize calendars with the duration of the calendar year caused confusion, until the concept of the leap year provided a way to make up for lost time. The solar or tropical year lasts for about 365.2422 days. No full-day calendar can match that number, and simply ignoring the seemingly small fraction creates a much bigger problem than one might suspect. The evidence lies in a long history of very changing dates and in the civil, agricultural and religious chaos that accompanies them.
Thirty dayes hath November,
April, June, and September,
Twenty-and-eight hath February alone,
And all the rest thirty-and-one,
But in the leape you must add one.
~Harrison, quoted by Denham
It takes three springs to make one leap year. ~The Comic Almanack
That’s why most of the modern world has adopted the Gregorian calendar and its leap year system to allow days and months to keep up with the seasons. A new mine could change it. SCIENCES How the asteroid killing dinosaurs prepared Earth for modern life. “Year of confusion” When Julius Caesar enjoyed his famous love affair with Cleopatra, Rome’s calendar had diverged from the seasons in about three months. But Egypt was observing a 365-day year, and as early as the third century BC. C. had even established the usefulness of a leap system to correct the calendar every four years. Julius adopted the system by decreeing a single year of confusion of 445 days (46 BC) to simultaneously correct the long years of drift.
This is Leap Year, and ancient proverbs say,
If lads don’t leap this year, the lasses may.
~Poor Sir Robin’s Almanac,” Observations upon the four Quarters of the Year,” 1792
The year of the sun consisteth of three hundred and sixty-five days and six hours, wanting eleven minutes; which six hours omitted, will, in time, deprave the compute: and this was the occasion of bissextile, or leap year. ~Brown, quoted by Johnson
Mudar bisiesto.—”To alter one’s course.”—”Bisiesto,” is the Spanish for our Bissextile or leap year. The proverb signifies that a man has begun to repent his follies. ~A Dictionary of Spanish Proverbs translated into English with explanatory illustrations by John Collins, 1823
The current Gregorian calendar system makes fractional days of the calendar year and leap year almost equal by occasionally omitting a leap day. This system produces an average annual life of 365.2425 days, only half a minute longer than the calendar year. At that rate, 3,300 years will pass before the Gregorian calendar also moves one day of our seasonal cycle. This means that future generations will have to make a decision in the leap year, even if not for long.
To find leap year you have this rule:—
Divide by iv, what’s left shall be,
For leap year 0, for past i, ii, and iii.
~Harris, quoted by Denham
During a Leap Year, as Leap Day approached, I began to have this sense I was to get what I always seem to need: an extra 24 hours in the day…. Then I started to think Leap Day should be designated a holiday so people can take advantage of the extra 24 hours however they wished…. By marking this bonus day in some special way, we would celebrate time—really consider what it means to have time here on Earth—and thus, be present with our life and our time together. ~Kara Douglass Thom, “Look Where You Leap,” Winning as a Fit Mom, 2015