That's it, keep it rising 

I think we will see quite a significant downward adjustment again this month. My rough calculations suggest the CET stands at 10.74C up to and including today which is some 0.3C below the provisional Hadley figure.

No real change expected in the final few days. I calculate the CET will finish at 10.77C which is 0.54C below the 1971-2000 mean and 0.89C below the 1981-2010 mean.

So it has been quite a cool month really. It is the maximum temperatures which are dragging us down. Minimums have been close to average this month. This is the reverse position from last month when the maximums were well above average whereas the minimums were slightly below average. So I think that is the reason why many people are saying this month has been poor. Daytime highs have been disappointing really whereas in April daytime temperatures were really rather good.

To put this into perspective the highest temperature recorded anywhere in the UK this month is just 22.7C at St James Park on the 11th. The next highest day is 21.5C. Down here in the south I have recorded a maximum of just 20.1C this month which is really poor. I managed 3 days over 20C last month with a high of 24.2C.

Looking back through my records the instances of maximum temperatures over 20C this May are the worst I have recorded since moving to my current location in late 2005. The lowest maximum before this year that I recorded in May was 22.7C in 2013. So to only manage 20.1C this year is distinctly poor. The overall mean maximum temperature for this May is not as low as 2013 but there has not been a single day I would describe as very warm.

...and as for the sunshine totals 

I'm on track for the dullest May I've recorded going back to 2003 (or even 2000 using external sources).

It may well finish more than 20 hours short of the previous record set in 2007... though still sunnier than June was that year 

Met Office Hadley       11.1c.      Anomaly      0.0c.   Provisional to 27th.

Metcheck                   11.05c.     Anomaly      -0.35c.

Netweather                11.58c.     Anomaly       0.29c.

Clevedon Weather      12.4c.       Anomaly      -1.0c.

Mount     Sorrel          11.4c.       Anomaly       0.1c.

My    Mean                 12.2c.       Anomaly       1.8c.

9.1C here (-0.9)

There's been about 62mm of rain which is the wettest month this year.
That's only just above the average of 57mm though.
Still seems quite dry from all the dry months before.
We're about 100mm down on the average for year at this point.

MET OFFICE HADLEY       11.1C.      Anomaly     0.0c.

Metcheck                        11.06c.    Anomaly    -0.35c.

Netweather                     11.6c.      Anomaly     0.3c.

Clevedon Weather           12.4c.      Anomaly    -1.0c.

Mount  Sorrel                  11.5c.     Anomaly      0.2c.

My    Mean                      12.3c.     Anomaly      2.2c.

Met Office Hadley       11.1c     Anomaly     -0.0c.    Provisional to 29th.

Metcheck                   11.0c.     Anomaly      -0.40c.

Netweather                11.55c.   Anomaly       0.26c.

Clevedon Weather       12.4c.    Anomaly       1.0c.

Mount   Sorrel             11.4c.    Anomaly       0.1c.

My   Mean                   12.2c.    Anomaly       2.1c.

Met Office Hadley       11.0c.      Anomaly      -0.1c.     Provisional to   30th.

Metcheck                   11.05c.     Anomaly      -0.36c.

Netweather                11.55c.     Anomaly       0.26c.

Clevedon Weather      12.4c        Anomaly      -1.0c.

Mount   Sorrel            11.4c       Anomaly        0.1c.

My   Mean                  12.2c       Anomaly        2.1c.

Looks like the final figure for May is in at 10.76C

Lower than any guesses but Hungry Tiger and Moomin75 were nearest with 11.0

So what was the final figure 10.8C or 11.0

11.0C according to Hadley.

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

That's the provisional figure excluding yesterday.

The final figure is as lanky says; 10.76C.

http://hadobs.metoffice.com/hadcet/cet_mean_2015

Wow, that is much lower than I thought it would be, my local mean was 11.4C, which suggests it was significantly cooler in northern England to pull the mean down.

Hadley has made it 10.8C

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

In my neck of the woods the May mean was 12.2c so large parts must have had a significantly cold May and it felt cold here for the most of it.

Its now June still chilly and im still having to put the bloody heating on for a couple of hours each day!

There has,bar the odd day here and there,no warmth at all this year,even when the sun has been out there is still a nagging chill in the air.

Keen to see GW's update WRT the competition!!

I'm not

So a relatively cool month is confirmed. The CET finished at 10.76C which is 0.55C below the 1971-2000 mean and 0.91C below the 1981-2010 mean. Only the second month to see the CET more than 0.5C below the 1971-2000 mean since November 2013 (August 2014 being the other month of course).

Nobody correctly predicted the CET this month. Everyone was too high with their predictions.

Looking at the maximum and minimum figures we see that the minimum CET was close to average whereas the maximum was a full 1C below the 1971-2000 mean and 1.4C below the 1981-2010 mean. That is why May felt rather disappointing for many of us.

The Spring CET has finished very close to average.

The warmest temperature anywhere in the UK in May was 23.8C at Faversham on the 11th. Looking back at the monthly reports on the Met Office website which go back to 2001 this is only the second May in that period which has failed to record a 25C somewhere in the UK. The maximum May temperature in 2013 was also 23.8C.

http://www.metoffice.gov.uk/climate/uk/summaries/2015/may

Temperature anomalies were lowest in the SE and highest in the NW

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/anomacts/2015/5/2015_5_MeanTemp_Anomaly_1981-2010.gif

The same can be said for rainfall

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/anomacts/2015/5/2015_5_Rainfall_Anomaly_1981-2010.gif

After a run of very sunny months May was a little disappointing for most

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/anomacts/2015/5/2015_5_Sunshine_Anomaly_1981-2010.gif

For Spring as a whole temperatures were close to average across the whole of the UK. Rainfall was well below average in the South and East but above average in the North West

http://www.metoffice.gov.uk/climate/uk/summaries/2015/spring

Despite a slightly poor May, sunshine as a whole was well above average during Spring in most places.

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/anomacts/2015/13/2015_13_Sunshine_Anomaly_1981-2010.gif

Annual CET competition - May update

Here are the updated tables for May. We have another new leader in NeilM closely followed by Hungry Tiger. There is then a large gap to John S2 in 3rd.

Thank you for the charts....

Thanks Simon. My performance this year is laughably poor. 

Many thanks as always GW!  Your time and effort is very much appreciated.

Congrats to the movers and shakers and indeed to all who took part!  As for me.  Ouch!!!