Friday the 13th is considered an unlucky day in Western superstition. It occurs when the 13th day of the month in the Gregorian calendar falls on a Friday, which happens at least once every year but can occur up to three times in the same year. For the 13th to fall on Friday, a month's first day must be a Sunday.
Origins
Unluckiness of 13
One source mentioned for the unlucky reputation of the number 13 is a Norse myth about twelve gods having a dinner party in Valhalla. The trickster god Loki, who was not invited, arrived as the thirteenth guest, and arranged for Höðr, the god of darkness, to shoot Balder, the god of joy and gladness, with a mistletoe-tipped arrow. Balder died, triggering much suffering in the world, which caused the number 13 to be considered unlucky.
Christian associations
The superstition seems to relate to various things, like the story of Jesus's Last Supper and crucifixion in which there were thirteen individuals present in the Upper Room on the thirteenth of Nisan Maundy Thursday, the night before his death on Good Friday.
In conjunction with Friday While there is evidence of both Friday and the number 13 being considered unlucky, there is no record of the two items being referred to as especially unlucky in conjunction before the 19th century.
The Knights Templar
Some cite the arrest of the Knights Templar on Friday, October 13, 1307, by officers of King Philip IV of France as the origin of the Friday the 13th superstition, but it is agreed the origins remain murky.
19th century
In France, Friday 13th might have been associated with misfortune as early as the first half of the 19th century. A character in the 1834 play Les Finesses des Gribouilles states, "I was born on a Friday, December 13th, 1813 from which come all of my misfortunes".
An early documented reference in English occurs in H. S. Edwards' biography of Gioachino Rossini, who died on Friday 13th of November 1868: "Rossini was surrounded to the last by admiring friends; and if it be true that, like so many Italians, he regarded Fridays as an unlucky day and thirteen as an unlucky number, it is remarkable that on Friday 13th of November he passed away."
Dissemination It is possible that the publication in 1907 of T. W. Lawson's popular novel Friday, the Thirteenth, contributed to popularizing the superstition. In the novel, an unscrupulous broker takes advantage of the superstition to create a Wall Street panic on a Friday the 13th.
Occurrence
Distribution Each 400-year Gregorian solar cycle contains 146,097 days (with 97 leap days) or exactly 20,871 weeks. Each cycle contains the same pattern of days of the week and therefore the same pattern of Fridays that are on the 13th. The 13th day of the month is very slightly more likely to be a Friday than any other day of the week.
{| class=wikitable style="margin-left: auto; margin-right: auto; border: none;" |+ Distribution of the 13th day per weekday over 4,800 months (400 years) |- style="vertical-align:center; text-align:center" ! Day of the week ! Monday || Tuesday || Wednesday || Thursday || Friday || Saturday || Sunday |- style="text-align:center;" ! Occurrences | 685 || 685 || 687 || 684 || 688 || 684 || 687
Any month that starts on a Sunday contains a Friday the 13th, and there is at least one Friday the 13th in every calendar year. The months with a Friday the 13th are determined by the Dominical letter (G, F, GF, etc.) of the year. Years which begin on the same day of the week and are of the same type (i.e. common year or leap year), will have a Friday the 13th in the same months.
This sequence, given here for 1900–2099, follows a 28-year cycle from 1 March 1900 to 28 February 2100:
+ Months with the 13th on a Friday for years from 1900 through 2100 Years during which a Friday the 13thoccurs in the month to the right(current and subsequent year are marked in bold) 1905, 1911, 1922, 1928, 1933, 1939, 1950, 1956, 1961, 1967, 1978, 1984, 1989, 1995; 2006, 2012, 2017, 2023, 2034, 2040, 2045, 2051, 2062, 2068, 2073, 2079, 2090, 2096 January 365: Sunday366: Sunday AAG 1903, 1914, 1920, 1925, 1931, 1942, 1948, 1953, 1959, 1970, 1976, 1981, 1987, 1998; 2004, 2009, 2015, 2026, 2032, 2037, 2043, 2054, 2060, 2065, 2071, 2082, 2088, 2093, 2099 February 365: Thursday366: Thursday DDC 1903, 1908, 1914, 1925, 1931, 1936, 1942, 1953, 1959, 1964, 1970, 1981, 1987, 1992; 1998; 2009, 2015, 2020, 2026, 2037, 2043, 2048, 2054, 2065, 2071, 2076, 2082, 2093, 2099 March 365: Thursday366: Wednesday DED 1900, 1906, 1917, 1923, 1928, 1934, 1945, 1951, 1956, 1962, 1973, 1979, 1984; 1990; 2001, 2007, 2012, 2018, 2029, 2035, 2040, 2046, 2057, 2063, 2068, 2074, 2085, 2091, 2096 April 365: Monday366: Sunday GAG 1904, 1910, 1921, 1927, 1932, 1938, 1949, 1955, 1960, 1966, 1977, 1983, 1988, 1994; 2005, 2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095 May 365: Saturday366: Friday BCB 1902, 1913, 1919, 1924, 1930, 1941, 1947, 1952, 1958, 1969, 1975, 1980, 1986, 1997; 2003, 2008, 2014, 2025, 2031, 2036, 2042, 2053, 2059, 2064, 2070, 2081, 2087, 2092, 2098 June 365: Wednesday366: Tuesday EFE 1900, 1906, 1917, 1923, 1928, 1934, 1945, 1951, 1956, 1962, 1973, 1979, 1984, 1990; 2001, 2007, 2012, 2018, 2029, 2035, 2040, 2046, 2057, 2063, 2068, 2074, 2085, 2091, 2096 July 365: Monday366: Sunday GAG 1909, 1915, 1920, 1926, 1937, 1943, 1948, 1954, 1965, 1971, 1976, 1982, 1993, 1999; 2004, 2010, 2021, 2027, 2032, 2038, 2049, 2055, 2060, 2066, 2077, 2083, 2088, 2094, 2100 August 365: Friday366: Thursday CDC 1901, 1907, 1912, 1918, 1929, 1935, 1940, 1946, 1957, 1963, 1968, 1974, 1985, 1991, 1996; 2002, 2013, 2019, 2024, 2030, 2041, 2047, 2052, 2058, 2069, 2075, 2080, 2086, 2097 September 365: Tuesday366: Monday FGF 1905, 1911, 1916, 1922, 1933, 1939, 1944, 1950, 1961, 1967, 1972, 1978, 1989, 1995, 2000; 2006, 2017, 2023, 2028, 2034, 2045, 2051, 2056, 2062, 2073, 2079, 2084, 2090 October 365: Sunday366: Saturday ABA 1903, 1908, 1914, 1925, 1931, 1936, 1942, 1953, 1959, 1964, 1970, 1981, 1987, 1992, 1998; 2009, 2015, 2020, 2026, 2037, 2043, 2048, 2054, 2065, 2071, 2076, 2082, 2093, 2099 November 365: Thursday 366: Wednesday D ED 1901, 1907, 1912, 1918, 1929, 1935, 1940, 1946, 1957, 1963, 1968, 1974, 1985, 1991, 1996; 2002, 2013, 2019, 2024, 2030, 2041, 2047, 2052, 2058, 2069, 2075, 2080, 2086, 2097 December 365: Tuesday366: Monday FGF
Frequency Although there is always at least one Friday the 13th per calendar year, it can be as long as 14 months between two Friday the 13ths. The longest period that occurs without a Friday the 13th is 14 months, either from July to September the following year being a common year starting on Tuesday (F) (e.g. 2018–19 and 2029-30), or from August to October the following year being a leap year starting on Saturday (BA) (e.g. 1999–2000 and 2027–28). The shortest period that occurs with a Friday the 13th is just one month, from February to March in a common year starting on Thursday (D) (e.g. 2026 and 2037).
On average, there is a Friday the 13th once every 212.35 days. Friday the 13ths occurs with an average frequency of 1.7218 per year or about 3477 since the year 1 CE.
Frequency within a single year There can be no more than three Friday the 13ths in a single calendar year; either in February, March, and November in a common year starting on Thursday (such as 2026 or 2037) (D), or January, April, and July in a leap year starting on Sunday (such as 2012 or 2040) (AG).
In the 2000s, there were three Friday the 13ths in 2009, and two Friday the 13ths in 2001, 2002, 2006, and 2007. In the 2010s, there were three Friday the 13ths in 2012 and 2015, and two in 2013, 2017, 2018, and 2019. In the 2020s, there were two Friday the 13ths in 2020, 2023 and 2024, as will be for 2029. There will also be three Friday the 13ths in 2026. The remaining years all have one Friday the 13th.
For the details see the table below; this table is for the Gregorian calendar and / for :
{| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;" |- style="vertical-align:center; text-align:center" ! Yearmodulo 28 || || 1700 2100 || 1800 2200 || 1900 2300 || Yearmodulo 28 |- | 06 17 23 || Jan Oct || Aug || Jun || Apr Jul || 06 17 23 |- | 01 07 18 || Apr Jul || May || Feb Mar Nov || Sep Dec || 01 07 18 |- | 02 13 19 || Sep Dec || Jan Oct || Aug || Jun || 02 13 19 |- | 03 14 25 || Jun || Apr Jul || May || Feb Mar Nov || 03 14 25 |- | 09 15 26 || Feb Mar Nov || Sep Dec || Jan Oct || Aug || 09 15 26 |- | 10 21 27 || Aug || Jun || Apr Jul || May || 10 21 27 |- | 05 11 22 || May || Feb Mar Nov || Sep Dec || Jan Oct || 05 11 22
Social influence According to the Stress Management Center and Phobia Institute in Asheville, North Carolina, an estimated 17–21 million people in the United States are affected by paraskavedekatriaphobia, the fear of Friday the 13th, making it the most feared day and date in history. Some people are so paralyzed by fear that they avoid their normal routines in doing business, taking flights or even getting out of bed. It has been estimated that US$ 800–900 million is lost in business on this day. Despite this, representatives for both Delta Air Lines and Continental Airlines (the latter now merged into United Airlines) have stated that their airlines do not suffer from any noticeable drop in travel on those Fridays.
In Finland, a consortium of governmental and nongovernmental organizations led by the Ministry of Social Affairs and Health promotes the National Accident Day (kansallinen tapaturmapäivä) to raise awareness about automotive safety, which always falls on a Friday the 13th. The event is coordinated by the Finnish Red Cross and has been held since 1995.
Rate of accidents A study by Scanlon, Luben, Scanlon, & Singleton (1993) attracted attention from popular science literature, as it concluded that "the risk of hospital admission as a result of a transport accident may be increased by as much as 52 percent on the 13th"; however, the authors clearly state that "the numbers of admissions from accidents are too small to allow meaningful analysis". Subsequent studies have disproved any correlation between Friday the 13th and the rate of accidents.
On 12 June 2008 the Dutch Centre for Insurance Statistics stated to the contrary, that "fewer accidents and reports of fire and theft occur when the 13th of the month falls on a Friday than on other Fridays, because people are preventatively more careful or just stay home. Statistically speaking, driving is slightly safer on Friday the 13th, at least in the Netherlands; in the last two years, Dutch insurers received reports of an average 7,800 traffic accidents each Friday; but the average figure when the 13th fell on a Friday was just 7,500."
Tattoo Holiday In recent years, Friday the 13th has emerged as a holiday for tattoo parlors and enthusiasts; with many shops running for 24 hours, and offering flash tattoos featuring the number 13 in the design. Some claim that having a number 13 tattoo can be an antidote to bad luck. According to Oliver Peck: "Bad luck would come your way, it would see the number 13, see that bad luck is already there, and it would pass on by."
Similar dates Similar dates are prevalent in many cultures, although it is unclear whether these similarities are in any way historically connected or only coincidental.
Tuesday the 13th in Hispanic and Greek culture In Hispanic countries, instead of Friday, Tuesday the 13th (martes trece) is considered a day of bad luck.