<Tr> <Td> 2012 (Wednesday) </Td> </Tr> <Tr> <Td> 2008 (Friday) </Td> </Tr> <P> 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 2008, 2012, 2016, 2020, and 2024 . A leap day is added in various solar calendars (calendars based on the Earth's revolution around the Sun), including the Gregorian calendar standard in most of the world . Lunisolar calendars (whose months are based on the phases of the Moon) instead add a leap or intercalary month . </P> <P> In the Gregorian calendar, years that are divisible by 100, but not by 400, do not contain a leap day . Thus, 1700, 1800, and 1900 did not contain a leap day; neither will 2100, 2200, and 2300 . Conversely, 1600 and 2000 did and 2400 will . Years containing a leap day are called leap years . Years not containing a leap day are called common years . February 29 is the 60th day of the Gregorian calendar, in such a year, with 306 days remaining until the end of the year . In the Chinese calendar, this day will only occur in years of the monkey, dragon, and rat . </P>

How many days are in febuary in a leap year