Why is Friday the 13th an unlucky day?

Explained! (Sort of.)

Black cat
(Image credit: <a href="http://shutr.bz/1daRxzJ">(Courtesy Shutterstock)</a><a></a>)

Why is Friday the 13th considered unlucky?

No one knows exactly, but the date has joined black cats, broken mirrors, and the Cleveland Browns in Western culture as harbingers of creepy misfortune. In fact, there's a term for people with a severe fear of the number 13. We call them "triskaidekaphobes."

But there are some theories as to why we relegate 13 to the bad things column, the most prevalent of which stems from Nordic myth. The story goes that once upon a time in the gilded halls of Valhalla, 12 Norse gods were throwing themselves a fancy dinner party, replete with lots of booze and magic fireballs. You know, ordinary god stuff. Peeved that he didn't get an invitation, Loki, the trickster god of mischief, ended up crashing the merriment as the uninvited 13th guest.

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What did Loki do?

The details are a bit complicated, but the short version is Loki put a major damper on the fun by tricking the blind god Höðr into shooting the beloved and nearly invincible god Baldr through the heart with an arrow fashioned from his one weakness: Mistletoe. (Incidentally, the story also explains why we kiss under the stuff come Christmastime. Gods are weird.)

A record screeched, Loki had a chuckle, and the rest of the Norse gods entered a long period of mourning. Dark times.

Where else is the number 13 considered unlucky?

The Bible, for starters. Ancient Christians may have started associating the number 13 with evil shenanigans when Judas — the disciple who sold Jesus out to Pontius Pilate — showed up late to the Last Supper to take a seat. The 12 others were already sitting.

What about the "Friday" part?

The crucifixion of Jesus was held shortly thereafter, on what's now become Good Friday.

But don't lots of accidents happen on Friday the 13th?

Actually, the reverse might be true. A 1993 traffic study of car accidents published in the British Medical Journal found that the number of accidents on one of London's busiest motorways actually decreased on Friday the 13th compared with other Fridays. Researchers, however, think this might simply be due to superstitious people choosing not to drive that day. The paper's authors told LiveScience that "although the data were authentic, the authors didn't mean for their conclusions to be taken seriously."

So I shouldn't hide under the covers on Friday the 13th?

I mean, you're free to do whatever you want! And it's worth noting that a few horrible, not-so-good things have happened throughout the course of human history on Friday the 13th (via the Telegraph):

  • Friday, October 13, 1307. King Philip IV of France orders the imprisonment of thousands of the Templars, a religious order of knights.
  • Friday, September 13, 1940. Buckingham Palace is hit by five German bombs, nearly killing both King George VI and the future queen, Elizabeth.
  • Friday, October 13, 1972. A Uruguayan air force plane disappears over the Andes. When 16 survivors turn up a few months later, it is revealed that they subsisted on the flesh of their fallen comrades.
  • Friday, September 13, 1996. Rapper Tupac Shakur is shot and killed in Las Vegas in an unsolved drive-by shooting. Conspiracy theories remain!

But as our pals at Mental Floss point out, Friday the 13th really isn't a big deal in other cultures: "Greeks and Spanish-speaking countries consider Tuesday the 13th to be the unluckiest day, while Italians steer clear of Friday the 17th," they write.

Still, plenty of people refuse to fly or get married on Friday the 13th, and many hotels will skip the 13th floor altogether, which reminds me of this old Mitch Hedberg bit (2:24):

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