This thread is for all comments, discussion, and analysis of temperatures in the UK during September, with particular emphasis on the Central England Temperature (CET), for the simple reason that it is the longest-running temperature series in the world with over 360 years of data. But you can comment on any interesting temperature statistics or data from across the UK, including your own backyard.
For those taking part in the competition, all CET predictions for September should be sent directly to me via the forum private message system. Please do not post them directly into the thread.
Historic CET summary for September
1981-2010 (30 years) 14.03C
1991-2020 (30 years) 14.17C
2001-2020 (last 20 years) 14.27C
Last year September was average at 14.0C. Actually the Setember CET has been very similar and very close to average for the past 4 years varying between 13.5C and 14.3C. 2016 was very warm with 16.0C and 2015 was cold with 12.7C.
Here is a chart of the September CET for all years since 1961
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Direct link to a larger version of the chart
Current model output
The first week shows 850s above average but that is deceptive due to lots of cloud. So unlikely to see surface temperatures much above average - mean of 21C for a few days in London. After that the 850s are close to average with a lot of scatter.
ECM (de Bilt) looks similar with temperatures struggling to push above 20C at any point.
Met Office contingency planners outlook
A 50/50 split between an average and a warm September based on the probabilities. The Met Office had almost the same split for August and we ended up with the average figure. I rather suspect the same will happen in September.
Precipitation also looks close to average. Another rather nondescript month in the offering I fancy.
A quick look at an interesting statistic. The CET figures for the last four months are remarkably similar to 2010.
Year May June July August
2010 10.7C 15.2C 17.1C 15.3C
2021 10.1C 15.5C 17.7C 15.8C
The only other year with a similar pattern is 1994 (although June was 1C colder than 2021). Nov 1994 was of course a record CET and it was followed by a very mild winter. My gut feeling is that this year will more closely follow 2010 than 1994, although I do not expect a negative CET in December.
September 2010 saw a CET of 13.8C. I expect 2021 to come in somewhere close to 14C.
Edited by moderator
01 November 2021 09:44:57
| Reason: Not specified