This thread is for all comments, discussion and analysis of temperatures in the UK during August, 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 back yard. 

For those taking part in the competition all CET predictions for September should be sent directly to me via the forum private message system. Do not post them directly into the thread. Deadline is extended to 23:59 on 2 September.

Historic CET summary for September

1971-2000 13.7C (30 years) 

1981-2010 14.0C (30 years) 

2000-2019 14.1C (last 20 years) 

The warmest September in recent times was 16.8C in 2006, the warmest of record. We also saw 16.0C ini 2016. There have also been a number of Septembers in the mid to high 13's (2007, 2008, 2010, 2013, 2017, 2018. Coldest September in recent times was 12.7C in 2015.

Although we think of September as having been a good month more often than not recently, in fact the September CET has only been at or above 14C in 5 of the last 13 years. 

Here is a chart of the September CET for all years since 1961

Direct link to larger version of the chart

Current model output 

GFS 850s looking mixed. Some warmer spells but often close to or slightly below average. Temperatures struggling to reach 20C in London.

GFS 850 https://www.wetterzentrale.de/de/show_diagrams.php?model=gfs&var=2&geoid=49069&lid=ENS&bw= 

GFS T2m https://www.wetterzentrale.de/de/show_diagrams.php?geoid=49069&model=gfs&var=5&run=12&lid=ENS&bw=

ECM looks cool for the first week of September but potentially for something warmer in the second week. 

ECM ENS T2m http://cdn.knmi.nl/knmi/map/page/weer/waarschuwingen_verwachtingen/ensemble/detail/ensemble-verwachtingen-detail10.png

Met Office contingency planners outlook

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/business/public-sector/civil-contingency/forecast-temp-son-v2.pdf

Autumn as a whole looking to be above average, based on probabilities.

September though does not look that warm. Most of the data points for September are at or below 14C. So looks like the probabilities are favouring a slightly cooler than average month.

Prediction sent.  

Met Office Hadley         13.8c.       Anomaly         -1.1c  Provisional to 1st.

Metcheck                      12.80       Anomaly         -0.92c

Netweather                   14.24c     Anomaly          0.55c

Peasedown St John      12.3c      Anomaly          0.23c    

Met Office Hadley         14.0c.        Anomaly         -0.9c. Provisional to 2nd.

Metcheck                      14.04c       Anomaly         0.32c

Netweather                   14.49c       Anomaly         0.8c

Peasedown St John      14.9c        Anomaly         2.57c

Met Office Hadley          15.0c       Anomaly         0.2c Provisional to 3rd.

Metcheck                       14.53c      Anomaly        0.81c

Netweather                    15.48c      Anomaly        1.79c

Peasedown St John       14.3c        Anomaly        1.77c.        

Met Office Hadley          15.0c       Anomaly         0.2c Provisional to 3rd.

Metcheck                       14.53c      Anomaly        0.81c

Netweather                    15.48c      Anomaly        1.79c

Peasedown St John       14.3c        Anomaly        1.77c.        

Climb, climb, climb!

(please! )

Met Office Hadley          14.8c        Anomaly       0.2c. Provisional to 4th.

Metcheck                       14.28c      Anomaly      0.56c

Netweather                    15.3c        Anomaly      1.61c

Peasedown St John       13.58c      Anomaly      1.1c. 

Met Office Hadley         14.6c.       Anomaly       -0.1c. Provisional to 5th.

Metcheck                      14.09c      Anomaly       0.36c

Netweather                   14.92c      Anomaly       1.23c

Peasedown St John      13.66c     Anomaly       1.13c.      

Did a rough estimate using the GFS 12z, which features a second warm spell, early the week after this coming one, that's been gaining ground across the models as a whole.

It lifts the estimate several into the 15s °C as of 16th, before a gradual slide toward the 14s during 17th-19th, after which a steeper drop occurs due to a 'cool high' moving over with some chilly nights. As of 22nd it's in the mid-14s °C.

Still a long way to go, so no need to panic if you went for something quite different this month.

Incidentally, I went sub-14 °C, believe it or not! 

Met Office Hadley      14.6c       Anomaly      -0.0c. Provisional to 6th.

Metcheck                   14.01c     Anomaly     0.21c

Netweather                14.79c     Anomaly     1.1c

Peasedown St John    14.6c.     Anomaly     2.7c.     

Met Office Hadley          14.5c        Anomaly       -0.1c. Provisional to 7th.

Metcheck                       14.33c      Anomaly       -0.61c

Netweather                    14.78c      Anomaly       1.09c

Peasedown St John      14.1c        Anomaly       1.57c.  

Met Office Hadley        15.0c        Anomaly        0.5c Provisional to 8th.

Metcheck                     14.85c      Anomaly        1.13c

Netweather                  16.29c      Anomaly        1.6c

Peasedown St John     14.5c       Anomaly        1.97c.    

Met Office Hadley           15.0c        Anomaly      0.5c. Provisional to9th.

Metcheck                        14.79c      Anomaly      1.13c

Netweather                     15.29c      Anomaly      1.75c

Peasedown St John       14.4c        Anomaly      1.87c. 

Met Office Hadley        14.9c        Anomaly       0.4c. Provisional to 10th.

Metcheck                     14.60c      Anomaly       0.88c

Netweather                  15.19c      Anomaly       1.5c

Peasedown St John     14.2c       Anomaly       1.67c.     

A sharp uplift from next week I reckon.

I'm toast this month having gone low 13's.

I've blown my shot at retaining the title too.

These heatwaves continue to crop up at next to little notice these days.

Rule of thumb for this competition from now on is take the 81-00 average and add 0.7c 

I'm toast this month having gone low 13's.

I've blown my shot at retaining the title too.

These heatwaves continue to crop up at next to little notice these days.

Rule of thumb for this competition from now on is take the 81-00 average and add 0.7c 

Something of a schoolboy error from Steve there, I made a similarly huge  mistake in July and that ruined my shot this year.

 

Something of a schoolboy error from Steve there, I made a similarly huge  mistake in July and that ruined my shot this year.

I never had a shot, but am reasonably happy with the 15c I went with. I think we'll see the CET reach the high 15's, but after that who knows - a cool week to end the month (or a high over us with cold nights) and we're back well into the 14s. But if the remaining month after the warm snap stays above average CET, when we could hit 16c

GW has far more important considerations at present, but I am very curious what people have gone for this month. The MO was giving out some conflicting signals so I'm expecting some big variation

I went for 14.9c pretty happy with that. CET could get close to 17c in about 10 days if the ECM is on the money.

I went for 14.9c pretty happy with that. CET could get close to 17c in about 10 days if the ECM is on the money.

 

14.9c (or 15c!) is a great estimate, if only a couple of people have gone higher - even if it were to end at 17c.

But if half (or more) entries are above you, then it's not at all great.

I would guess that you and I will be about two-thirds up the table for this month once we have the ranked list.