February 29

This wiki is created at February 29, which is a special day.

February 29, also known as leap day or leap year day, is a date added to most years that are divisible by 4, such as 2016, 2020, and 2024. A leap day is added in various solar calendars (calendars based on the Earth's revolution around the Sun). Lunisolar calendars (whose months are based on the phases of the Moon) instead add a leap month.

Years containing a leap day are called leap years. Years not containing a leap day are called common years.

A leap day is observed because the Earth's period of orbital revolution around the Sun takes approximately six hours longer than 365 whole days. A leap day compensates for this lag, realigning the calendar with the Earth's position in the Solar System; otherwise, seasons would occur later than intended in the calendar year.

Leap days can present a particular problem in computing known as the leap year bug when February 29 is not handled correctly in logic that accepts or manipulates dates. For example, this has happened with ATMs and Microsoft's cloud system Azure.

Born on February 29
A person born on February 29 may be called a "leapling", a "leaper", or a "leap-year baby". Some leaplings celebrate their birthday in non-leap years on either February 28 or March 1, while others only observe birthdays on the authentic intercalary date, February 29.