If you're a paraskevidekatriaphobic — someone frightened by Friday the 13th — this is going to feel like a very long year. The bad times for you started just this morning.

Most years have two Friday the 13ths. This year, though, there are three of them — April 13 and July 13, too. And as Wade Malcolm of The News Journal in Wilmington, Del., points out, they are exactly 13 weeks apart. It happened in 2009 and will happen again in 2015.

It doesn't usually happen during a Leap Year, which this is, University of Delaware math professor Tom Fernsler told the newspaper. And that won't again until 2040.

Fernsler's nickname, by the way, is reportedly Dr. 13. And he says that 95 percent of people are superstitious about the day. "The other 5 percent are liars."

The phobia, by the way, goes by other names. Wikipedia calls fear of Friday the 13th friggatriskaidekaphobia.

The article says fear of the Friday and 13 combo is relatively new, a terror that emerged only in the 19th century, though Friday has apparently been fear-inducing for some time. The first evidence of it folklorists could find was Henry Sutherland Edwards' 1869 biography of Gioachino Rossini. It's theorized that it is actually an unhappy wedding of two previous thoughts: that 13 is unlucky. And so's Friday. Of course the combo would lead to major trembles — most of them good-natured and giggly.

Spanish-speaking countries, by the way, are wary of the dreaded Tuesday the 13th. That does not appear to have its own series of popular scary movies.

Much-loved mythbuster Snopes says "the reasons Friday came to be regarded as a day of bad luck have been obscured by the mists of time — some of the common theories link it to a signficant event in Christian tradition said to have taken place on Friday, such as the Crucifixion, Eve's offering the apple to Adam in the Garden of Eden, the beginning of the Great Flood or the confusion at the Tower of Babel." Chaucer, it notes, alluded to Friday as a day on which bad things seemed to happen in the Canterury Tales, as far back as the late 14th century."

Among the things you're not supposed to do on Friday: needlework, harvesting, launching a ship, beginning a sea voyage, starting a journey, giving birth, getting married, getting over being ill, hearing news (sorry about that), moving or starting a new job.

As for the bad reputation of 13, it may stem, sources agree, from the fact that Judas Iscariot was said to be the 13th guest at the Last Supper in Christian tradition.

LiveScience is celebrating the day with 13 superstitions good and bad, from the horror-inducing appearance of a black cat to the serendipity of the just-discovered penny.

Of Friday the 13th, it quotes Thomas Gilovich, a psychologist at Cornell University: "If anything bad happens to you on Friday the 13th, the two will be forever associated in your mind. All those uneventful days in which the 13th fell on a Friday will be ignored."