Unlucky Friday 13 is mostly a Western thing on the Gregorian calendar.
Both the day Friday and the number 13 are considered unlucky, but there is no evidence of the two together being unlucky before the 19th century.
17 to 21 Million people affected in the US
According to the Stress Management Centre and Phobia Institute in North Carolina, an estimated 17 to 21 million people in the United States are affected by a fear of this day. Some people are so paralyzed by fear that they avoid their normal routines in doing business, taking flights or even getting out of bed.
Black cats have nothing to do with Friday the 13th or any so called evil for that matter. From the Middle Ages, they have been associated with witches and witchcraft, myths that have been perpetuated by Hollywood. Major celebrities like Norman Reedus, Morgan Freeman, Robert Redford, Elizabeth Taylor, Brigit Bardot, Nicole Kidman and John Travolta have all had black cats.
Fear of Friday the 13th is called paraskevidekatriaphobia, from the Greek words Paraskeví for Friday and dekatreís for thirteen.
The Last Supper
Judas, the apostle believed to have betrayed Jesus, is believed to be the 13th guest at the Last Supper. But according to the Gnostic lost Gospel of Judas, Jesus asked Judas to betray him. The Gospel of Judas contains conversations between Jesus and Judas Iscariot.
13 Comes after 12
Thomas Fernsler an associate policy scientist in the Mathematics and Science Education Resource Centre at the University of Delaware says the number 13 suffers because of its position after 12. Twelve is considered a complete number – 12 months in a year, 12 signs of the zodiac, 12 gods of Olympus, 12 labours of Hercules, 12 tribes of Israel, and 12 apostles of Jesus – whereas 13 is not. But were there 12 or 13 apostles?
Friday, the Thirteenth – a 1907 novel
It is possible that the publication in 1907 of Thomas W. Lawson’s popular novel Friday, the Thirteenth, contributed to the superstition spreading. In the novel, an unscrupulous broker takes advantage of the superstition to create a Wall Street panic on a Friday the 13th.
The Knights Templar
A suggested origin of the superstition is that Friday, 13 October 1307, was the date on which Philip IV of France arrested hundreds of Knights Templar. This date is mentioned in the 1955 Maurice Druon historical novel The Iron King, John J. Robinson’s 1989 work Born in Blood: The Lost Secrets of Freemasonry, Dan Brown’s 2003 novel The Da Vinci Code and Steve Berry’s The Templar Legacy (2006).
Automotive safety Awareness in Finland
In Finland, a consortium of governmental and nongovernmental organizations led by the Ministry of Social Affairs and Health, promotes 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.
Traffic incidences in the UK
A study in the British Medical Journal concluded that there “is a significant level of traffic-related incidences on Friday the 13th as opposed to a random day, such as Friday the 6th, in the UK.”
The fear of the number 13 is so common that many buildings around the world skip the thirteenth floor, with the numbers going straight from twelve to fourteen.
Twice in 2018
Friday the 13th occurs at least once every year but it can occur up to three times in the same year. In 2018 it will occur twice – on April 13 and July 13. There will be two Friday the 13ths every year until 2020, where 2021 and 2022 will have just one occurrence, in August and May respectively.
Of course it’s irrational
For many people superstitions are based more on cultural habit than conscious belief. If you are surrounded by certain beliefs and superstitions they are probably going to affect you in some way or another whether tongue in cheek or for real.