On Jan 1, 8:47*pm, John Hall wrote:
In article ,





writes:
Comparing 2001-2010 with 1981-2010 gives the following for each month:

January +0.37C
February +0.91C
March +0.58C
April +0.49c
May +0.29C
June +0.22C
July +0.37C
August +0.79C
Sepetember +0.38C
October +0.38C
November +0.78C
December -0.20C

You will notive that December is the only month that appears to be
getting cooler. *All of the others are warming.

Clearly one very cold December will have more of an effect on the
2001-2010 mean than it will on the mean for a period three times as
long. If one argued that December 2010 was just one freak month, and so
compared the December means for 1981-2009 with 2001-2009, would there
still be a cooling trend?
--
John Hall
* * * * * * * *"I look upon it, that he who does not mind his belly,
* * * * * * * * will hardly mind anything else."
* * * * * * * * * * * * * * * * * * * * * *Dr Samuel Johnson (1709-84)- Hide quoted text -

- Show quoted text -

If we assume that the anomaly for Dec 2010 was -5°C the effect of
this will be to lower the 2001-2010 mean anomaly by 0.5 degC, a large
amount. This entirely removes the negative relative anomaly for
December 2001-2010 compared with 1981-2010, though the positive
anomaly that would result is less than that for most other months. So
I think is it is fair to say that December has got colder recently,
relative to what one might expect. This sort of variation is not
uncommon. Often a month, or sometimes two, is colder or warmer than
usual for a few years, maybe a decade, then reverts to normal. The
same thing is seen, probably more markedly, with rainfall.

Tudor Hughes, Warlingham, Surrey.