Leap Year

A leap year (or intercalary or bissextile year) is a year containing one additional day (or, in the case of lunisolar calendars, a month) in order to keep the calendar year synchronized with the astronomical or seasonal year. Because seasons and astronomical events do not repeat in a whole number of days, a calendar that had the same number of days in each year would, over time, drift with respect to the event it was supposed to track. By occasionally inserting (or intercalating) an additional day or month into the year, the drift can be corrected. A year that is not a leap year is called a common year.

For example, in the Gregorian calendar (a common solar calendar), February in a leap year has 29 days instead of the usual 28, so the year lasts 366 days instead of the usual 365. Similarly, in the Hebrew calendar (a lunisolar calendar), Adar Aleph, a 13th lunar month is added seven times every 19 years to the twelve lunar months in its common years to keep its calendar year from drifting through the seasons.

The term leap year gets its name from the fact that while a fixed date in the Gregorian calendar normally advances one day of the week from one year to the next, in a leap year it will advance two days due to the year's extra day (thus "leaping over" one of the days in the week). For example, Christmas Day fell on Saturday in 2004, Sunday in 2005, Monday in 2006 and Tuesday in 2007 but then "leapt" over Wednesday to fall on a Thursday in 2008.

Other articles related to "year, leap year, leap years, years":

Revised Bengali Calendar
... The length of a year in the Bengali calendar, as in the Gregorian calendar, is counted as 365 days ... To make up this discrepancy, the Gregorian calendar adds an extra day, to make a leap year, to the month of February every fourth year (except in ... calculations, did not make this extra leap year adjustment ...
Bengali Calendar - Leap Year
... In this calendar, seven is subtracted from the year, and the result is divided by 39 ... If after the division the remainder (= (year - 7) / 39) is zero or is evenly divisible by 4, the year is then designated as a leap year and contains 366 days, with the ... There are 10 leap years in every 39 years, although an extraordinary revision may be required over a long time ...
Egyptian Christians - Calendar - Coptic Year
... The Coptic year is the extension of the ancient Egyptian civil year, retaining its subdivision into the three seasons, four months each ... days each and an intercalary month at the end of the year of 5 or 6 days, depending whether the year is a leap year or not ... The year starts on 29 August in the Julian Calendar or on the 30th in the year before (Julian) Leap Years ...
Leap Year - Birthdays - Hong Kong
... the legal birthday of a leapling March 1 in common years The time at which a person attains a particular age expressed in years shall be the commencement of the anniversary corresponding to the date of ... Where a person has been born on February 29 in a leap year, the relevant anniversary in any year other than a leap year shall be taken to be March 1 ...
Hebrew Month - Principles - Worked Example
... Given the length of the year, the length of each month is fixed as described above, so the real problem in determining the calendar for a year is determining the ... The day of Rosh Hashanah and the length of the year are determined by the time and the day of the week of the Tishrei molad, that is, the moment of the average conjunction ... Given the Tishrei molad of a certain year, the length of the year is determined as follows First, one must determine whether each year is an ordinary or leap year by its position in the 19-year Metonic cycle ...

Famous quotes containing the words year and/or leap:

Material advancement has its share in moral and intellectual progress. Becky Sharp’s acute remark that it is not difficult to be virtuous on ten thousand a year has its applications to nations; and it is futile to expect a hungry and squalid population to be anything but violent and gross.
Thomas Henry Huxley (1825–95)

Iambics march from short to long;—
With a leap and a bound the swift Anapaests throng;
Samuel Taylor Coleridge (1772–1834)