Sorry late again. Please place your May CET predictions in this thread. Deadline for entries is 23:59 on Monday evening (2nd May).

May historic data summary

Here is the usual rundown of historic data for previous years.

Long run averages:
1971-2000: 11.3C
1981-2010: 11.7C
1996-2015: 11.8C

The CET in May has been fairly consistent over the past 20 years. Generally between 11.5C and 13C. We have though had few cooler years of late with the CET under 11C. Last year we saw 10.8C and in 2013 just 10.4C. Warmest May recently was 2008 with 13.4C. Coldest was 1996 with only 9.1C.

Here is a chart of the May CET since 1961 with a 10 year moving average

Here are some details of what the models and forecasters generally are saying at the moment

GEFS (850 and 2m temps)

http://www.wetterzentrale.de/pics/MT2_London_ens.png

http://www.wetterzentrale.de/pics/MT8_London_ens.png

http://www.wetterzentrale.de/pics/MT2_Manchester_ens.png

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

Good agreement for a significant warm up after the first few days of the month. This signal has been there for at least a week now so it looks highly likely that some decent Spring warmth is finally on the way. The question is how long will it last.

ECM
https://cdn.knmi.nl/knmi/map/page/weer/waarschuwingen_verwachtingen/ensemble/detail/ensemble-verwachting-detail15.png

De Bilt ensembles also showing a decent warming trend

Met office
http://www.metoffice.gov.uk/media/pdf/h/s/A3_plots-temp-MJJ_v1.pdf

Contingency planners forecast suggests an equal probability of warmer or colder than average temperatures in May. No particular trend is evident.  

Pattern matching (JFF)
The pattern matching had it right for April with a strong signal for cooler than average conditions. For May there is no real signal at all. If we look at earlier years where both March and April have been cool we see no signal for May. Sometimes it is warm, sometimes average and sometimes cool. So no help there.

What we can see is that a cool May almost always occurs where at least a couple of months earlier in the year were below average. However, just because there were some cool months earlier in the year does mean May will be cold as sometimes it is warm in those circumstances. So I think that ties in nicely with the contingency planners assessment. Basically almost anything is possible in May.

Here is a first look at the May CET

Current estimate to the 14th of May suggests the CET could be as high as 12.2C which is 1.3C above the 1981-2010 mean and 1.7C above the 1971-2000 mean. This is despite the first 4 days of the month being below average. 

11.5c   For Me please.  Thank you for running CET Watch..

10.8C for me please

12.7 for me this month please

11.66c thanks

(Please see my later post on page 4)12.2 please for me. I think we're in for a big warm up the next 4 months. With average and very warm spells dominating. I just hope la nina's effects will hold off for August. This month I will go for 1c above the 61-90 average. 

I'm inclined to agree with you,Weatherfan, we are long overdue a very warm may and I ve a feeling after this weekend temperatures will rise significantly with 20c+ being commonplace by mid month and thereafter.I don't think we`ll be breaking the record CET for May of 15.2c but we might come close this year.So I'm going to go for 13.5c,not brave enough to go higher but would not be surprised if my prediction turns out too low.

I'll go for

11.5C

11.9C please GW

Think it could be a warm one. 13.25c please

Thanks GW

I'll take a punt at 11.7 this month please & thank you.

Difficult to say, but I think I'll go for 11.5 C, please.

12.25c

Put the wrong figure in first time  

12.3c please 

11.6C please. No idea why.

Time to be bold - 13.3*C please!

Where's the fun in this otherwise 

12.9C please GW.