List of non-standard dates
Several non-standard dates are used in
Historical
January 0
January 0 or 0 January is an alternative name for December 31. January 0 is 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 also 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]
February 30
February 30 or 30 February is a date that does not occur on the Gregorian calendar, where the month of February contains only 28 days, or 29 days in a leap year. However, from a historical perspective February 30 has been used at least once and appears in some reform calendars.
The thirteenth-century scholar
February 30 was a day that happened in Sweden, 1712.
To avoid confusion and further mistakes, the Julian calendar was restored in 1712 by adding an extra leap day, thus giving that year the only known actual use of February 30 in a calendar. That day corresponded to February 29 in the Julian calendar and to March 11 in the Gregorian calendar.[5][6] The Swedish conversion to the Gregorian calendar was finally accomplished in 1753, when February 17 was followed by March 1.[5]
Artificial calendars may also have 30 days in February. For example, in a climate model the statistics may be simplified by having 12 months of 30 days. The
February 31
February 31 or 31 February is exceptionally used on gravestones when the date is unknown,
May 35
May 35 or 35 May is used in mainland China to avoid censorship when referring to the
December 31.5 GMT
"December 31.5 GMT" in 1924 almanacs was an instant defined to solve the contrast between two different conventions in defining the civil time of referring to midnight as zero hours.[12]
December 32, 1980
The LearAvia Lear Fan aircraft test flight had British government "funding that expired at the end of that year." After the cancellation of a planned test flight on December 31, 1980, due to technical issues, the first prototype made its maiden flight on January 1, 1981, but the date was officially recorded by sympathetic British government officials as "December 32, 1980".[13]
Software
Several non-standard dates are also used in programming. In Microsoft Excel, the epoch of the 1900 date format is January 0, 1900.[14] February 31 is used (along with February 32 and February 33) for calculating weather data, and March 0 or 0 March is used often in software engineering.[15][16]
Other uses
March 0 is used in astronomy.[17]
Fictional calendars
In the works of
February 30, 1951, is the last night of the world in Ray Bradbury's short story "Last Night of the World".[19]
June 31 is a fictional date in the Soviet film 31 June. It is also the date of a fictional RAF raid on Germany in Len Deighton's 1970 novel Bomber.
December 32 or 32 December is the date of Hogswatchnight in Hogfather by Terry Pratchett. It has also been used as a title for various works.
The children's book Please Try to Remember the First of Octember! by Dr. Seuss narrates many delightful things which are supposed to happen starting on the first day of the fictional month of Octember.
In popular culture
March 0 is used in
In November 2010 it was discovered that a Hanshin Tigers wall calendar incorrectly included the date November 31. Fans who had bought the calendar were given a sticker to cover up the date, and reprinted calendars were sent.[22]
In the episode "94 Meetings" of the sitcom Parks and Recreation, Ron Swanson is forced to deal with 94 meetings in a single day because his assistant, April, scheduled them all for March 31st (instead of the common fake date of February 31st), mistakenly believing it was not a real date.
Soul band
Reform calendars
Because evening out the lengths of the months is part of the rationale for reforming the calendar, some reform calendars, such as the World Calendar and the Hanke–Henry Permanent Calendar, contain a 30-day February. The Symmetry454 calendar assigns 35 days to February, May, August, and November, as well as December in a leap year.
See also
- Ides of March
- List of calendars
- Time formatting and storage bugs
- System time
- Tibb's Eve, a day said to occur neither before nor after Christmas
- Undecimber
References
- ^ "Leap Seconds". Time Service Department, United States Naval Observatory. Archived from the original on February 28, 2012. Retrieved December 31, 2006.
- ^ Ransom, David H. Jr. (November 19, 1989). "Program ASTROCLK: Astronomical Clock and Celestial Tracking Program with Celestial Navigation". p. 110.
- ^ Roscoe Lamont, "The Roman calendar and its reformation by Julius Caesar", Popular Astronomy 27 (1919) 583–595. Sacrobosco's theory is discussed on pages 585–587.
- ^ "February 30 Was a Real Date". timeanddate.com. Retrieved April 25, 2016.
- ^ ISBN 87-7423-083-2.
- ^ Vallerius, Johannes (1711). Allmanach på åhret effter Christi födelse 1712. Lund, Sweden.
- ^ "Hadley Centre: GDT netCDF conventions". MetOffice.com. November 22, 2005. Archived from the original on November 22, 2005. Retrieved March 21, 2017.
- ^ "February 31 On Gravestone". Swampy Acres Farm Blog. December 19, 2018. Archived from the original on December 19, 2018. Retrieved June 13, 2019.
- ISBN 9780760759431.
- ^ McBride Jacobson, Molly (January 6, 2017). "St. Omer Cemetery Witch Grave". Atlas Obscura.
- ^ "China tightens information controls for Tiananmen anniversary". The Age. Australia. Agence France-Presse. June 4, 2009. Retrieved November 3, 2010.
- ISBN 0-935702-68-7.
- ^ "Lear Fan 2100 (Futura)". The Museum of Flight. 2009. Archived from the original on July 12, 2009. Retrieved November 27, 2009.
- ^ Lowe, Scott (May 11, 2007). "How do I... Perform basic formatting in Excel 2003?". TechRepublic.
- S2CID 130637323.
- ISBN 978-0-07-160890-9.
- ISBN 978-0-11-887320-8.
- ISBN 978-0-395-08256-0.
- ^ "A Classic Ray Bradbury Esquire Story". esquire.com. June 6, 2012. Retrieved March 21, 2017.
- ^ Graham, S. W. (July 1995). "The Doomsday Rule". people.se.cmich.edu. Retrieved April 1, 2023.
- ^ Greene, Andy (March 2, 2018). "Lin-Manuel Miranda, 'Weird Al' Yankovic Talk New 'Hamilton Polka'". Rolling Stone. Retrieved March 2, 2018.
- ^ "阪神タイガース、来年のカレンダーに". Nikkei (in Japanese). November 28, 2010. Archived from the original on February 27, 2019. Retrieved December 13, 2023.
- The Oxford Companion to the Year. Bonnie Blackburn & Leofranc Holford-Strevens. Oxford University Press 1999. ISBN 0-19-214231-3. pp. 98–99.