Leap years only come round once every four years (fact #1), so it cannot be considered negligent if you don’t keep up to date about the calendar correction process.

To plug up the knowledge gaps, here are 28 more things you need to know about the anomalous date.

2) A leap year (also known as an intercalary or bissextile year) is a year containing one additional day as a corrective measure – February 29 in the Gregorian calendar − in order to keep the calendar year synched with the astronomical or seasonal year.

3) However, in the Hebrew calendar a 13th lunar month is added seven times every 19 years to the twelve lunar months in its common years to keep the calendar year from drifting through the seasons too rapidly.

4) Years that are evenly divisible by 100 do not contain a leap day, apart from those years that are evenly divisible by 400, which do, For example, 1900 did not contain a leap day while 2000 did.

5) The Gregorian calendar repeats itself every 400 years, which is 20,871 weeks including 97 leap days.

6) Over this period, February 29 falls 13 times on a Sunday, Tuesday, or Thursday. Fridays or Saturdays occur 14 times. And Mondays or Wednesdays will crop up 15 times.

7) While adding a day every four years is seen as the best solution, it is slightly inaccurate to go with the mathematic logic and calculate an additional six hours for each year. The Earth makes a complete revolution around the sun in 365 days, 5 hours, 49 minutes, and 16 seconds.

8) The marginal difference of 0.000125 days between the Gregorian calendar average year and the actual year means that, in 8,000 years, the calendar will be about one day behind where it is now.

9) Anyone born on February 29 may be called a “leapling” or a “leaper”. In common years they usually celebrate their birthdays on February 28 or March 1.

10) However, in China, the Civil Code since 10 October 1929 implies that the legal birthday of a leapling is February 28 in common years.

11) Hong Kong meanwhile considers the legal birthday of a leapling as March 1 in common years, having done so since 1990.

12) Leaplings will technically enjoy less birthday anniversaries than their age in years

13) In Gilbert and Sullivan’s comic opera The Pirates of Penzance, the character of Frederic the pirate apprentice is nobbled when he discovers that he is bound to serve the pirates until his 21st birthday rather than until his 21st year.

14) Notable leap year births include: Gioachino Rossini (1792), Italian composer who is the subject of today’s Google doodle; William A. Wellman (1896), American film director who directed 1927 movie Wings, the first film win an Academy Award for Best Picture at the 1st Academy Awards ceremony; actor Joss Ackland (1928); radio presenter Jono Coleman (1956) rapper Ja Rule (1976); footballer Darren Ambrose (1984); and a Philadelphia typesetter (1904), recognised as having the longest surname ever used. The typesetter’s full name was reported to be  Adolph Blaine Charles David Earl Frederick Gerald Hubert Irvin John Kenneth Lloyd Martin Nero Oliver Paul Quincy Randolph Sherman Thomas Uncas Victor William Xerxes Yancy Zeus Wolfeschlegelsteinhausenbergerdorffvoralternwarengewissenhafschaferswessenschafewarenwohlgepflegeundsorgfaltigkeitbeschutzenvonangreifendurcihrraub-gierigfeindewelchevoralternzwolftausendjahresvorandieerscheinenwanderersteerdemenschderraumschiffgebrauchlichtalsseinursprungvonkraftgestartseinlange-fahrthinzwischensternartigraumaufdersuchenachdiesternwelchegehabtbewohnbarplanetenkreisedrehensichundwohinderneurassevonverstandigmenschlich-keitkonntefortplanzenundsicherfreuenanlebenslanglichfreudeundruhemitnichteinfurchtvorangreifenvonandererintelligentgeschopfsvonhinzwischenster-nartigraum, Senior.

15) On the flip side, prominent deaths on February 29 include: John Whitgift, Archbishop of Canterbury (1604); gunslinger Pat Garrett; and poet Ruth Pitter (1908).

16) The only notable person known to have both been born and died on February 29 was Sir James Wilson (1812–1880), Premier of Tasmania.

17) According to astrologers, people born under the sign of Pisces on February 29 have unusual talents and personalities reflecting their special status.

18) The odds of being born on a leap day are 1 in 1500.

19) Karin Henriksen of Norway gave birth to three children on consecutive February 29ths – a daughter in 1960 and two sons in 1964 and 1968.

20) The Keogh family of Ireland and the UK saw a one generation born on February 29 1940, his son born on the same date in 1964 and a granddaughter arrive on the 29 in 1996.

21) The European Football Championship and summer Olympic Games always fall in leap years, happening as they do every four years.

22) Remember the ditty you learned as a kid to help you remember how many days there are in each month? No? Well here it is again:

“Thirty days hath September,

April, June and November;

All the rest have thirty-one

Save February, she alone

Hath eight days and a score

Til leap year gives her one day more.”

23) It is not known when the ‘ladies’ privilege’ of being able to propose on February 29 dates back to exactly, but it was mentioned in a book called Courtship, Love, and Matrimony in 1606.

24) Should the man refuse the female suitor, tradition has it that she should be compensated with £1, a kiss or a silk gown. She is expected to wear a red petticoat while proposing.

25) For anyone looking to make a leap year proposal, a prayer is now available. The Church of England have released the prayer asking for God’s blessings on the engaged couple, going on to suggest that wedding planning should not overtake the “more important” preparation for a lifetime together. It reads:

“God of love, please bless N and N/as they prepare for the commitment of marriage./May the plans for the wedding not overtake/the more important preparation/for their lifetime together./Please bless their family and friends/as they prepare for this special day/and may your blessing be upon them now and always./Amen.”

26) In Greece, marriage in a leap year is considered unlucky. One in five engaged couples in Greece plan to avoid getting hitched in a leap year.

27) The tradition in Denmark is that a refusal from the man proposed to must compensate the unlucky lady with 12 pairs of gloves.

28) Leap year folklore contends that beans and peas planted during a leap year “grow the wrong way”.

29) The Scots seem to have their doubts about the worth leap years, too. A saying dictates that the prospects for livestock are bleak: “Leap year was never a good sheep year.”

And fittingly, an extra one for luck: 30) Sweden (and Finland) had a “double” leap year in 1712, with two days being added to February – there was a February 30 in 1712. This was done because the leap year in 1700 was dropped, and Sweden’s calendar was not synched with any other calendar. By adding an extra day in 1712, they were back on the Julian calendar.

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