In article
,
Teignmouth writes:
Not sure if I'm reading this correct, and it's from Wikipedia, but 3
Standard Deviations = 1 in 370 years, 4 Standard Deviations = 1 in
15,787 years, and 5 Standard Deviations = 1,744,277 years.
http://en.wikipedia.org/wiki/Normal_distribution

I've calculated the December mean from 1971 - 2009 as +5.0c, with a
Standard Deviation of 1.5c, so by my calculations the current CET that
is running at -2.0c is somewhere between 4 & 5 Standard Deviations.


But you aren't comparing like with like. There is going to be much
greater variation in the average for a spell of 7 days (1st to 7th
December) than there is for the whole month. If the average CET for the
whole month turned out to be -2.0C - or even anywhere near that - then
it really would be something.
--
John Hall
"I look upon it, that he who does not mind his belly,
will hardly mind anything else."
Dr Samuel Johnson (1709-84)