WHAT A DIFFERENCE A DAY MAKES
365.2422 in one year
Check your calendars -- Leap Day returns
Feb. 29 comes once every four years -- or so

Steve Rubenstein, Chronicle Staff Writer

Sunday, February 29, 2004

Leap Day, the thing that gets shoehorned into the calendar to keep things on the cosmic up-and-up, is here to remind the world to
hold its horses. It's not March yet. Not until midnight.

Like the Olympic Games and the presidential mud brawl, Leap Day happens once every four years, whether people want it to or not.
Actually, there's little to say about Leap Day that wasn't said precisely four years ago. Also eight, 12 and 16 years ago.

The idea behind leap days is to prevent the 365-day calendar from running too far ahead of the time it takes the Earth to circle the sun,
which is 365. 2422 days. Without leap days, Christmas would eventually fall during summer. The Giants might even win the World Series.

For those keeping track, today happens to be the first Leap Day of the millennium, because Leap Day 2000 was technically the last
Leap Day of the last millennium.

Four years ago, there was a lot of Leap Day fuss because of the rule that says century years -- those that end in "00" -- do not have
leap days. Except that those century years divisible by 400 -- such as 2000 -- do have leap days.

But this year is just an ordinary leap year, with an ordinary Leap Day.

The Tiffany and Co. jewelry stores took out a big ad to remind people that Leap Day is the "one day when girls can pop the question.''
Tiffany would also like to remind people that it has engagement rings for $1.3 million, a sum than can make boys pop the answer of "no.''

The Goodyear tire people are giving away free rides on their blimps to people born on Leap Day. There is a catch. The blimp is in Akron,
Ohio. Leap Day people must pay their own way to get to Akron and, even more important, must pay their own way to leave Akron.

For their part, the blimp people are taking no chances with fake leap babies. "You must prove your birthday is Feb. 29 by driver's license,
passport or birth certificate, and the documentation must be an original, not a copy,'' say the official blimp rules.

The Honor Society of Leap Day Babies is all excited. Every four years it reminds people that many famous people were born on Leap Day
such as Hermann Hirschboch, Alfred Sendrey and Alan Richardson. Those gentlemen were all composers, and if no one has heard of 
hem, the society people say it's not their fault.

Bandleader Tommy Dorsey's brother, Jimmy, was a Leap Day baby. Astronaut Jack Lousma (who almost got to fly to the moon but had
to settle for Skylab) was a Leap Day baby Democratic Rep. Bart Stupak of Michigan (who was named this year's "friend of the paper
industry'') was a Leap Day baby.

Pope Paul II was a Leap Day baby. Today he is known as the last Renaissance pope, although not while he was alive, because nobody
knew that the Renaissance was ending.

The society is asking leap babies on which day -- Feb. 28 or March 1 -- they celebrate their birthdays during non-leap years. This is a
sore point for many leap babies, who say they get deprived of more gifts than Christmas Day babies.

Some leap babies celebrate Feb. 28, because February is their birth month. Other leap babies celebrate March 1 because March 1 is
the 60th day of the year during non-leap years and Feb. 29 is the 60th day of the year during leap years.

Leap babies like to argue about these things on leap-baby Web sites. The Feb. 28 celebrators call themselves "strict Februarians.''
Occasionally, leap babies have been known to lose their tempers on the subject.

The Honor Society for Leap Day Babies is trying to get "Leap Year Day'' officially designated on the calendar. "If Groundhog Day is on
the calendar, why not Leap Year Day?'' says the society, not without reason.

People have a 1 in 1,461 chance of being a leap baby, so leap babies are not particularly rare. But Elan Schmitt of San Francisco and
her identical twin, Desiree -- who were born on Leap Day 1980 -- are a little more rare. They have been sending out announcements to
remind people how rare they are.

"I think it's a cosmic thing that happened to us,'' said Elan, who called her sister on her cell phone to talk about it. Desiree said she
knew it was Elan calling before she even picked up the phone -- although she confessed that it had less to do with twin-sister psychic
bonding than with caller ID. "Yes,'' agreed Desiree. "The spaceship's going to be coming for us soon.''

One outfit that takes its leap days seriously is the National Weather Service, which maintains Leap Day records. The warmest Leap Day
ever in San Francisco was in 1992, when it was 71 degrees. The coldest San Francisco Leap Day was in 1888, when it was 42 degrees.
The wettest was in 1976, when it rained 1.34 inches.

None of those marks is particularly remarkable, said forecaster Ryan Walbrun, because there are only one-fourth as many Feb. 29ths as
any other day.

"You are not going to see as many extremes, statistically,'' said Walbrun, who added that he and his fellow forecasters spent many long
hours last week debugging the weather service computer so Feb. 29 "would have the right records and climatology.''

He also said that the weather "has no way of knowing" that it's Feb. 29 instead of March 1.

For those who plan to be around in the year 4000, one final fact is worth pointing out. That year, and its multiples -- 8000, 12000, etc. --
will not be leap years, as there is an exception to the every-fourth-century exception. There are no exceptions to that exception, at least
not yet.

E-mail Steve Rubenstein at srubenstein@sfchronicle.com.

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