Thanks my friend.

Incidentally, GW, what year would you say we're most closely following in terms of being so far above average, then flipping cold in August?

Met Office Hadley       15.5c.      Anomaly     -0 .5c     provisional to 22nd.

Metcheck                   15.43c.     Anomaly      -0.79c.

N-W                           15.92c.    Anomaly      -0.29c.

Mount Sorrel               15.65c.    Anomaly      -0.55c.

My mean                     16.2c.     Anomaly      -1.3c.

Incidentally, GW, what year would you say we're most closely following in terms of being so far above average, then flipping cold in August?

Thanks Kevin!

Incidentally, GW, what year would you say we're most closely following in terms of being so far above average, then flipping cold in August?

1921 is close although April and May were average

If we look at years with a CET mean of 10C or more in the Jan - Jul period followed by a cold August there are not many since 1900.

In addition to 1921 as mentioned by Kevin above, we have 1957 and 1992. Both of these years had one cool month in the first 7 though - in 1957 it was May and in 1992 it was January.

Looking further back 1794 is a reasonable match although that year had a very cold January. 1737 also fits well although Feb and Mar were average but August was very cold at 13.8C.

1686 is perhaps the best example. July was only average (although that is average by reference to 1971-2000) but August came in at 14.5C.

Of those 6 years 3 had fairly average Septembers and 3 had cold Septembers.

Thanks GW!

2014 looking like a really unique year at the moment, then?

One thing I have noticed of late is that temperatures have become very volatile. Recently of course we have had some very warm months until this month. But not so long ago we had a run of very cold months.

In fact only one of the last 20 months has finished within 0.5C of the 1971-2000 mean. That is very unusual. The last time we had a longer run than this was 1985-1987. From August 1985 to August 1987 we had 25 consecutive months with only 1 coming in within 0.5C of the 1971-2000 mean. This was of course a very cool period. 8 months were more than 0.5C above the 1971-2000 mean but 16 were more than 0.5C below the 1971-2000 mean.

The stats below show some figures for recent years. As you would expect if we take the 1971-2000 period we get roughly 4 months each year within 0.5C of the mean, 4 months more than 0.5C warmer and 4 months more than 0.5C cooler. There is a slight bias towards the warmer months.

The period from 1997-2009 stands out as being much warmer with an average of 6.7 months per year more than 0.5C above the mean and only 1.5 months below with about 4 being average.

The period from 2010-2013 was of course much cooler and we see the warm months fall back to the 4.3 figure that is in line with the 1971-2000 mean. However there were 5.5 months on average more than 0.5C below the mean.

The last 2 years from Sept 2012 show a different trend again. This time we have a significantly higher number of warm and cold months with 5.5 and 5 respectively on average each year. Only 1.5 months per year on average were close to the mean.

If we look at the number of months that have seen a CET 1C or more higher or lower than the 1971-2000 mean there again has been an increase in volatility recently. Going back to 1960 we find that only in 5 years have there been 8 or more months in the year where the temperature has been greater than 1C or more either side of the mean. All of those years have occurred since 1989. Even 1962 and 1963 only saw seven months.

The years in question are 1989, 1995, 1999, 2006, 2011 and 2013. Both 1989 and 2013 saw 9 months with a temperature at least 1C warmer or colder than the mean. All the other years had 8 months.

So far in 2014 we have had 6 months out of 8 with an anomaly of 1C or more.

These anomalies have not increased due to a rise in average temperature as the table below shows. The middle column shows the average number of months with a temperature anomaly of 1C or more. The final column shows the mean CET for the whole period.

The mean temperature for the years 2010-2013 was very similar overall to the 1971-2000 mean but there were an average of 7.3 months with an anomaly of 1C or more compared to the mean of 5.6 months. The table shows that trend has been increasing gradually in recent years but seems to have accelerated significantly since 2011. The figure for 2011-2013 is 7.7 months. That is though largely down to two exceptional years falling close to each other (2011 and 2013). Both 2010 and 2012 saw only 6 months each. However, if 2014 also comes in at either 8 or 9 months that will be 3 years out of the last 4 with 8 months or more having 1C+ temperature anomalies which would be unprecedented.

So temperatures do seem to be becoming more volatile. Will this trend continue over the next few years?

The CET now stands at just 15.14C by my calculations after a return of 12.28C today.

Another chilly one tomorrow with 11.7C expected. Monday will see higher minimums but lower maximums but slightly warmer overall at 12.7C. By Monday we are looking at the CET dropping down to just 14.90C.

From Tuesday onwards the CET should stay fairly flat for the rest of the month. Current estimate is a final figure of 14.89C.

The CET now stands at just 15.14C by my calculations after a return of 12.28C today.

Another chilly one tomorrow with 11.7C expected. Monday will see higher minimums but lower maximums but slightly warmer overall at 12.7C. By Monday we are looking at the CET dropping down to just 14.90C.

From Tuesday onwards the CET should stay fairly flat for the rest of the month. Current estimate is a final figure of 14.89C.

A sub 15C CET is certainly a cool summer month.

The CET should just dip below 15C today based on the minimums this morning. Other than at Pershore the CET minimums were not that low this morning. But even so another chilly start. Temperatures recovering nicely now though.

See the ground frost thread for details of a national record broken in Northern Ireland this morning. Coldest August air minimum on record with -1.9C at Katesbridge.

Thanks GW.

I notice the models are generally looking more unsettled for Thu/Fri this morning and even the weekend not looking that settled. 

Will help keep temps under 15c maybe?

Re. volatility, could be releated to the decrease in solar activity?

Not going down much.. Given temperature forecast over the last days of the month will expect it to be just a little lower...

Met Office Hadley         15.4c.     Anomaly      -0.6c.    Provisional to 23rd.

Metcheck                      15.27c.   Anomaly     -0.96c.

N-W                             15.77c    Anomaly     -0.44c.

Mount Sorrel                 15.50c.   Anomaly     -0.76c.

My Mean                       16.1c.     Anomaly     -1.4c.

As expected my CET calculation now stands at 14.99C. It will drift gradually lower over the rest of the month except on Thursday which may see a bit of a jump back up purely due to some very high overnight minimums being forecast.

Currently expecting the CET to finish at 14.90C.

First look at the September CET. At the moment the first week of the month looks like seeing a very quiet period of weather with temperatures very slightly below average. This looks the more likely scenario at the moment rather than the plume that ECM is trying to show this morning.

Met Office Hadley       15.2c.    Anomaly      -0.7c.   Provisional to 24th.

Metcheck                   15.20c.  Anomaly      -1.02c.

N-W                          15.66c   Anomaly      -0.54c.

Mount Sorrel              15.46c.  Anomaly      -0.74c.

My  Mean                   16.0c.    Anomaly      -1.5c.         

First look at the September CET. At the moment the first week of the month looks like seeing a very quiet period of weather with temperatures very slightly below average. This looks the more likely scenario at the moment rather than the plume that ECM is trying to show this morning.

Thanks GW

As you get through to September ane even more so for October, the exact positioning of any anticyclone becomes the critical factor as charts that you would assume are going to deliver above average temperatures can be relatively cool depending on the exact nature of the airmass within the high pressure.

My feeling for September at the moment is probably slightly above average (low 14's maybe) but will wait and see a while longer.

13.1C (-1.2) here now, will very likely go below 13C as nothing much warmer expected before September.
That would make August close to the September mean.

Here 11.2c

Mean min 6.6c

Mean max 15.8c