Welcome to Friday the 13th!

It wasn't until about 9am this morning that I realized that today was both a Friday, and the 13th of the month. Significant! … enough that I had no idea.

I spent part of the day working in javascript on a twitter search project for spudart (I may post it here in a few days), and thought maybe it'd be fun to write a quick program to list all the upcoming "Friday the 13th"'s… or not. I ended up checking wikipedia and found a list going up to 2028 (en.wikipedia.org/wiki/Friday_the_13th#Occurrence).

Interesting notes from the article:
This year only has one Friday the 13th – today.
Next year has 3: January, April, and July
A month beginning on Sunday will have a Friday the 13th.
The longest we can go without having a Friday the 13th is fourteen months.

For a 4,800 month (400 year) Gregorian cycle, the 13th of the month will fall on Friday 688 times, making Friday the most common weekday for the 13th to occur on.
The occurrences are as follows:
Sunday – 687
Monday – 685
Tuesday – 685
Wednesday – 687
Thursday – 684
Friday – 688
Saturday – 684

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  1. Tom said,

    I believe it was last year or maybe the year before that we had 3 Friday the 13ths. I'm glad to know that we only have one this year, not that I'm overly supersticious or anything +tap wood+

    May 16, 2011 @ 11:26 am

  2. sparx said,

    It was 2009. (February, March, and November)
    2010 also only had one. (August)

    May 16, 2011 @ 1:49 pm

  3. janet said,

    The 13th is my day. In 1978 on Friday October 13th I delivered twin boys. Ironically I did not know I was carrying twins! Oh what a happy day…..
    Then, on Saturday, November 13th, 1982 another son was born!
    so, I embrace the 13th and the #3. note, I also had twin 4th cousins from Key west, Fl born on October 13th, 1949.

    June 6, 2011 @ 3:39 pm

  4. sparx said,

    How do you go 9 months without realizing there are two human worm monkeys inside of you?

    June 6, 2011 @ 3:46 pm

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