Many believe it is UNLUCKY because Judas Iscariot double-crossed Jesus on the date, Friday 13 October, 1307. So they believe if someone gets #13, it betrayed him/her.
THERE WERE 13 PEOPLE AT THE LAST SUPPER.
And tradition has held that the 13th to take their seat was either Judas or Jesus himself.
A WITCHES' COVEN HAS 13 MEMBERS.
Although a coven is now considered to be any group of witches (or vampires, in some tellings), it was once believed that a coven was made up of exactly 13 members.
13 LETTERS IN A NAME MEANS THE PERSON IS CURSED.
There’s an old superstition that says if you have 13 letters in your name, you’re bound to be cursed. Silly, yes, but slightly more convincing when you consider that a number of notorious murderers' names (Charles Manson, Jack the Ripper, Jeffrey Dahmer, Theodore Bundy, and Albert De Salvo) all contain 13 letters.
12 IS A PERFECT NUMBER, SO 13 MUST BE UNLUCKY.
In some schools of numerology, the number 12 is considered to be the representation of perfection and completion. It stands to reason, then, that trying to improve upon perfection by adding a digit is a very bad idea indeed—your greed will be rewarded with bad luck.
MANY BELIEVE EITHER THE LAST SUPPER OR THE CRUCIFIXION OCCURRED ON THE 13TH.
One of the great controversies surrounding the Last Supper is whether or not it was a Passover meal. John seems to suggest that the meal was eaten the day before Passover, which has led some scholars to date the Last Supper to the 13th of Nisan (a month on the Jewish calendar), while others say that the crucifixion itself was on the 13th of Nisan.
WHAT ASTROLOGY SAY
LANGUAGE OF 13
In Hindi, it’s called as 'Terah', which means 'your’s'. It represent your karmas. In the spiritual context, it could also mean that every thing belongs to one God/Creator including the soul present in every human being
13 AND IT'S CONNECTION WITH FEMINITY
In ancient cultures, the number 13 represented femininity, because it corresponded to the number of lunar (menstrual) cycles in a year (13 x 28 = 364 days). The theory is that, as the solar calendar triumphed over the lunar, the number thirteen became anathema.
IT IS A SIGN OF BAD LUCK
For the superstitious, this number brings bad luck or misfortune. This dates back to Biblical times. Judas who betrayed Jesus is said to be the thirteenth disciple. Also, the thirteenth chapter of the Revelation is reserved to the antichrist and to the beast. It is also the day when Christ is said to have died on the Cross.
Not all bad
The fortune teller on the other hand predicts a better future on Friday 13. In France, as soon as there is a Friday 13 to the calendar, the National Lottery organises a special drawing because some choose that day to bet money.
Explanation: