How did Fridays and number 13 become the power couple of doom?

It’s a day associated with misfortune, superstition and a movie franchise featuring a serial killer in a hockey mask.

But what is it about Friday the 13th that makes some people avoid ladders, airplane travel and black cats?

The number 13 has long been a sign of bad luck, in Western culture, at least.

So much so that 80% of  high-rise buildings do not have a 13th floor, according to National Geographic. Hotels skip over Room 13. Some airports don’t have a Gate 13 or a row 13 in seating.

Here is a look at how Fridays and 13 came together as the power couple of doom and gloom.

A scene from "Friday the 13th, Part VI: Jason Lives," from left: C.J. Graham  and Wallace Merck
A scene from "Friday the 13th, Part VI: Jason Lives," from left: C.J. Graham and Wallace Merck

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Triskaidekaphobia vs. paraskevidekatriaphobia

Fear of the number 13 is called triskaidekaphobia and its earliest declaration of being an unlucky number dates to the Middle Ages in Europe.

Fear of Friday the 13th is called paraskevidekatriaphobia.

Most triskaidekaphobiacs are also paraskevidekatriaphobic.

Most estimates suggest that 17 to 21 million people suffer from triskaidekaphobia, according to Donald Dossey, a folklore historian and founder of the Stress Management Center and Phobia Institute in Asheville, North Carolina.

How did Fridays and 13th become synonymous with super bad luck?

In Biblical tradition, Fridays are considered unlucky, a concept predating the “Good Friday” crucifixion of Jesus Christ. Friday is said to be the day that Adam and Eve ate the forbidden fruit from the Tree of Knowledge; the day the Temple of Solomon was toppled; Cain killed his brother Abel, and the day Noah’s ark set sail in the Great Flood.

But no historical record exists definitively connecting Fridays and the number 13 as a bad luck combo platter before the 19th century.

A visitor watches "The Last Supper" (Il Cenacolo or L'Ultima Cena), Italian artist Leonardo da Vinci's late 15th-century mural painting housed by the refectory of the Convent of Santa Maria delle Grazie in Milan, on February 10, 2021. The convent reopens to the public four days a week through February 9 - 21, 2021.
A visitor watches "The Last Supper" (Il Cenacolo or L'Ultima Cena), Italian artist Leonardo da Vinci's late 15th-century mural painting housed by the refectory of the Convent of Santa Maria delle Grazie in Milan, on February 10, 2021. The convent reopens to the public four days a week through February 9 - 21, 2021.

How did the number 13 get such a bad reputation?

It is commonly linked to the early Christians, as the number 13 appears in certain Biblical traditions.

The most well known is the betrayer Judas was believed to be the 13th Apostle to join the table at the Last Supper.

More than 100 Knights of the Templar — a large organization of devout Christians during the medieval era — were believed to have been tortured and later killed by King Philip IV of France on Friday, Oct. 13, 1307.

Viking mythology also isn’t fond of 13.  Loki is believed to be the 13th god who showed up uninvited to the Banquet of Valhalla. The god Baldr was soon killed accidentally by his brother, using a spear given to him by Loki and the whole earth went dark in mourning.

The oldest known negative reference to 13 is found in the Mesopotamian Code of Hammurabi, a Babylonian code of law that dates to approximately 1760 BC. The laws are numbered, but number 13 is omitted.

Black cats are considered harbingers of doom on Friday the 13th, according to supersition.
Black cats are considered harbingers of doom on Friday the 13th, according to supersition.

Do more unfortunate mishaps happen on Friday the 13th?

Most of the United States shut down for COVID on Friday, March 13, 2020, the day the national emergency was declared for the pandemic, but like most things Friday the 13th connected it's probable a coincidence.

A 1993 study that attracted attention from popular science literature 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.” But the study also noted "the numbers of admissions from accidents are too small to allow meaningful analysis."

Subsequent studies disproved any correlation between Friday the 13th and the rate of accidents including a 2008 study from the Dutch Centre for Insurance Statistics. It found 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 more careful or stay home.

What do numerologists say about the number 13?

Some consider it unlucky because it falls after the number 12, which is considered a “perfect” number: 12 months in a year, 12 apostles, 12 tribes of Israel, 12 labors of Hercules, 12 gods of Olympus, 12 hours on a clock.

Autographed bust of Jason from "Friday the 13th" on display at Asylum Records on August 19, 2023, in Chandler, AZ.
Autographed bust of Jason from "Friday the 13th" on display at Asylum Records on August 19, 2023, in Chandler, AZ.

How often is there a Friday the 13th

In the Gregorian calendar, the 13th day of the month falls on a Friday, at least once a year, but can occur up to three times in the same year. This year, and next year, there are two Friday the 13ths. There were two each year between 2017 and 2020.

The rare three Friday the 13s in a year occurred in 2012 (the same year the Mayan calendar’s 13th Baktun ended prompting apocalyptic predictions) and 2015. The next time will be in 2026.

Any famous people born on Friday the 13th?

Absolutely. “Full House” moguls Mary Kate and Ashley Olsen and actress Kat Dennings were born on June 13, 1986. So were actors Steve Buscemi (Dec. 13, 1957), Julia Louis-Dreyfus (Jan. 13, 1961) , Kate Walsh (Oct. 13, 1967), Christopher Plummer (Dec. 13, 1929), Hootie and the Blowfish lead singer Darius Rucker (May 13, 1966) and legendary horror thriller director/screenwriter Alfred Hitchcock (Aug. 13, 1899).

Rapper Tupac Shakur, shown in this Dec. 16, 1993 file photo, died six days after being shot in September 1996 in a drive-by attack in Las Vegas. Rapper Notorious B.I.G., whose real name was Christopher Wallace, was gunned down as he left a party in Los Angeles on March 9, 1997, police said, becoming the second high-profile gangsta rap artist slain in the last six months.

Any famous deaths associated with Friday the 13th?

Indeed. Tupac Shakur was killed in Las Vegas on Friday Sept. 13, 1996. OG TV chef Julia Child died on Aug. 13, 2004; Kitty Genovese was murdered in front of 38 witnesses who didn’t call police on March 13, 1964; NASCAR driver Tony Roper died Oct. 13, 2000 after a high-speed accident; mobster Mickey Spillane was shot and killed as he left his Queens NYC apartment on May 13, 1977.

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This article originally appeared on Bucks County Courier Times: Why is Friday the 13th unlucky? How it became unluckiest day of year