MOUNT VERNON — “Thirty days hath September, April, June and November. All the rest have 31, except February alone, to whom we 28 assign ’til leap year gives it 29.”
Many a child memorized a version of that verse in an attempt to keep the confusing phenomenon of leap year somewhat straight.
There’s a Feb. 29 this year, which means 2008 is a leap year.
But why is there an extra day in the calendar every four years? Turns out the universe operates much more logically than humanity does, and leap year evolved as an attempt to align the two. The evolution of intercalary years, or leap years, is an interesting story of humans’ attempt to “fix” a calendar that’s not quite right.
The Farmers’ Almanac explains that in the astronomical year, the seasons repeat every 365.2422 days, but our calendar has just 365 days in each year.
The Roman emperor Julius Caesar, in 46 B.C., first decreed that the calendar would have 365 days, organized into 12 months. Previously, the Romans had followed a Greek lunar calendar that didn’t fit the seasons either. Its year ended approximately a quarter of a day early, the result of which was that the calendar was a full day off track every fourth year.
Caesar’s calendar — known as the Julian calendar — added an extra day to February every fourth year to correct this discrepancy, making the length of the Julian year 365.25 days long, too long by 11 minutes and 14 seconds. Thus, explains the Farmers’ Almanac, after 128 years his calendar would be a full day off from the astronomical year.
It wasn’t until 1582 that Pope Gregory XII ordered a correction to the Julian calendar, resulting in its becoming known as the Gregorian calendar, still in use today. Its length is 365.244 days, which means it misaligns with the astronomical calendar every 3,322 years. Nonetheless, that extra day every four years is still necessary.
Non-leap years are called common years and are comprised of 52 weeks and one day. Thus, if a person’s birthday is on Tuesday in a common year, it will be on Wednesday the next common year, and on Thursday the next. But since a leap year has 52 weeks and two days, if a birthday was on Tuesday in a common year and the following year is a leap year, the birthday figuratively “leaps” over Wednesday and occurs on Thursday.
Those who were born on Feb. 29 have no actual birthday to celebrate except during leap years, but they get their choice of celebrating on Feb. 28 or March 1 instead.
Lifelong Mount Vernon resident Joyce Swingle will be 88 years old on Friday, even though she’s only 22 according to her actual birthdays. When she was a child, she celebrated her birthday with her family on March 1 every year that wasn’t a leap year, along with her uncle, who was born on the first day of March.
“We celebrated my birthday on Feb. 29 on leap year, but my uncle said, ‘The other three years, we’ll celebrate together.’ My son always thought it was very funny that eventually he was older than his mother. But I do get a year older every year,” she said.
Swingle was told by her family that she was the only baby born on Feb. 29 in 1920 in Mount Vernon, but that another baby girl, coincidentally also named Joyce, was born that same day in Fredericktown. Swingle is not acquainted with that woman.
In previous centuries, women could propose to men during a leap year, a tradition that started with the dubious legend that St. Bridget — in the days when nuns were allowed to marry — once proposed to St. Patrick. Because he’d taken a vow of celibacy, he had to decline, but the tradition grew to the point that Scotland passed a law in 1288 giving women the right to propose in leap years. If the man refused, he was compelled to pay the woman a pound. One wonders how many enterprising women made some extra pocket money during leap years.