February 30. February 30 occurs in some calendars, but not in the Gregorian calendar, where February contains only 28, or in a leap year, 29 days.
February 30 is usually used as a sarcastic date for referring to something that will never happen or will never be done.[1] Swedish calendar[edit] Swedish calendar for February 1712 Instead of changing from the Julian calendar to the Gregorian calendar by omitting a block of consecutive days as had been done in other countries, the Swedish Empire planned to change gradually by omitting all leap days for the entire period from 1700 to 1740 inclusive.
Although the leap day was omitted in February 1700, the Great Northern War began later that year, diverting the attention of the Swedes from their calendar so that they did not omit leap days on the next two occasions and 1704 and 1708 remained leap years. The Swedish conversion to the Gregorian calendar was finally accomplished in the usual way in 1753, by omitting the last 11 days of February. In J.R.R. January 0. January 0 is an alternative name for December 31.
In an ephemeris[edit] January 0 refers to the day before January 1 in an annual ephemeris. It keeps the date in the year for which the ephemeris was published, thus avoiding any reference to the previous year, even though it is the same day as December 31 of the previous year.January 0 occurs in the epoch for the ephemeris second, "1900 January 0 at 12 hours ephemeris time".[1] 1900 January 0 (at Greenwich Mean Noon) was also the epoch used by Newcomb's Tables of the Sun, which became the epoch for the Dublin Julian day.[2] In technology[edit] See also[edit] March 0. March 0 is an imaginary date.
This formulation may be used in software such as Microsoft Excel to refer to the last day of February as a way of allowing for the fact that its length varies in leap years.[1] It can also be used as a term for half-birthdays of people born on August 29, 30 and 31. [citation needed] "March 0" is sometimes used by astronomers as a synonym for the last day of February.[2] See also[edit] February 31. February 31, with regard to the modern Western (revised Gregorian) calendar, is an imaginary date.
It is sometimes used for example purposes, to make it clear regardless of context that the information being presented is artificial and not real data.[1] February 30 is sometimes used in the same manner, although there are other calendars that legitimately use February 30. In this respect, these "dates" are similar to other clearly fictional data used for a similar purpose, such as the 12th of Never or "John Q. Public". Examples of deliberate usage[edit] This gravestone in the Old Mission Church Cemetery in Upper Sandusky, Ohio, shows the date of death for Christiana Haag as February 31, 1869. Gravestone in the graveyard of the deconsecrated church of St Peter-in-the-East, Oxford, which reads:[2] "[T]he world's first February 31 Party! Births[edit] See also[edit] References[edit]