Where in the World Is “Tuesday the 13th” Considered Bad Luck?

If you thought Friday the 13th was the only date you had to worry about, it’s probably best not to spend much time in Spain, Greece, or Latin America. Just as in many Western countries, the thirteenth day of the month is also considered unlucky there, but only if it falls on a Tuesday.

Why Tuesday? The superstition is linked to the Spanish word for Tuesday, martes, named for the Roman god of war, Mars (the equivalent of the Greek god Ares). In Greek, Tuesday is known as Triti, meaning third, and bad luck is said to come in threes. Thus, the day is associated with violence and bad omens, as demonstrated in a Spanish proverb that translates as: "On Tuesday, don’t get married, embark on a journey, or move away.”

To make matters even more confusing, Italy considers Friday bad luck, but only when paired with the 17th day of the month. One reason for this belief could be that the Roman numerals for 17, XVII, can be shifted to spell out the Latin word vixi ("I have lived”), which is a euphemism for death.

The origin of the unluckiness of the number 13 is disputed, though one of the most common explanations is that there were 13 people at the table during the Last Supper, including Judas, who would betray Jesus (Likewise, one of the reasons why Friday is considered unlucky could be because Jesus was crucified on Good Friday.) Another story comes from Norse mythology: the trickster god Loki arrives uninvited as the thirteenth guest at a dinner party and tricks the blind god Höðr into shooting Baldr with a mistletoe-tipped arrow.

Yet the combination of Friday and the number 13 has only been considered unlucky in Western nations since the 19th century. It was popularized by the 1907 novel Friday, the Thirteenth, in which a Wall Street panic is caused by that superstition. More recently, the horror movie franchise Friday the 13th, which started in 1980, has made the date an indelible part of American pop culture.

Lucky or unlucky?