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Summer temperature trend

Posted: Wed Sep 21, 2016 9:31 am
by Len Wood
No apparent trend over this time frame
summer trend.jpg
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Re: Summer temperature trend

Posted: Wed Sep 21, 2016 6:23 pm
by Nicholas Gardner
Len, my record only goes back to 2005. I suspect the exceptionally warm summer of 2006 and then the very poor summers of 2007, 2008, 2011 & 2012 have had an influence somewhat. These wet/cool summers were rather exceptional (to me they were) and led to some of the worst summer weather I have ever experienced. Thankfully, since 2013 things seem to have reverted back to something more normal.
ottervalleysummermeantemp.png
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Re: Summer temperature trend

Posted: Thu Sep 22, 2016 2:48 pm
by Martin Rowley
... I maintain a couple of series which try to capture the 'goodness'/'badness' of summers based on sunshine and maxima - the two parameters that most people would judge a summer by. There's a lot of 'fudging' involved due to changes of equipment, locations, units of measurement etc., but I believe that the graphs below capture the broad trends OK.

As you can see [spot values are individual years/black line rolling 10-year mean ending at the tenth year], although recent summers continue the generally 'good' summers since the second-half of the 1980s, in recent years there has been a gentle downturn in values.
LondonSummerIndex_1900_LATEST.gif
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SouthWessexSummerIndex_1900_LATEST.gif
SouthWessexSummerIndex_1900_LATEST.gif (13.49 KiB) Viewed 12331 times

Re: Summer temperature trend

Posted: Fri Sep 23, 2016 9:52 pm
by Len Wood
The longterm Plymouth record is broadly in agreement with your indices Martin.

There is a small longterm warming trend shown by the black dotted line.
The record is smoothed by 10 yr running means shown in red.
Three periods of relatively warm summers show up.
Just like your graphs, there is a small decrease in summer temperature in the last few years.
JJA trend.jpg
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