July 2011 and the 823 years email

We’ve all had it, haven’t we?

Not that. Get your mind out of the gutter.

No. I’m talking about the “There are 5 Fridays, 5 Saturdays and 5 Sundays in [month] – this won’t happen again for 823 years” email.

I got it about October last year and I’ve had another million copies delivered because *shock* it’s happening in July 2011 too. What are the chances of two of the possible seven occurrences of this “once in every 823 years” event happening just a few short months apart?
We live in privileged times indeed.

Except that it’s obviously untrue. You know it, I know it, we all know it. Apart from the people who keep forwarding this nonsense, of course.

In actual fact, every month with 31 days has to have 3 x 5 of something. Otherwise there wouldn’t be enough days to fill it up. And, even allowing for leap years, the maximum time between these months with any 5 x 3 given days is 11 years. In fact, because of leap years, this phenomenon follows a set 6-5-6-11 pattern (as confirmed by Snopes.com).

So, July 2005 had 5 Fridays, 5 Saturdays and 5 Sundays, July 2011 will have 5 Fridays, 5 Saturdays and 5 Sundays and so will July 2016, July 2022 and July 2033.
I’ve been doing some rudimentary calculations and I reckon that rather than having just one more of these “Moneybags” July months in the next 823 years, we’re actually looking good for 29 of them. Bingo.

Obviously, this goes for any combination of 3 x 5 days in any given 31 day month.

Thus, next time you get that email, reply to sender with a link to this page and stop them from spreading the stupidity yet further.

2 thoughts on “July 2011 and the 823 years email

  1. I got the email where if you looked at a specific time on a specific day for only a few short minutes then a star would be so close to earth it would appear as if we had 2 suns.

    Obviously fake. No need to even go near Snopes to figure that out. Yet people believe it.

    After all, they got it on email you know.

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