This month has been warmer than several Octobers and one May since 1990:

December 2015 9.8C (est)

October 1982 7.8C
October 1983 8.5C
October 2003 9.2C
October 2008 9.7C
May 1996 9.1C

Great post here from the Met Office with all the stats on the rain and heat this month

http://www.metoffice.gov.uk/news/releases/archive/2015/early-dec-stats

Thanks very much for your comments.

Just calculated the mean minimum temperature for Bournemouth Hurn this month and it is 9.4C. Compare that to the 1981-2010 mean which is 1.6C and you have an anomaly of 7.8C.

The 1981-2010 mean maximum for December at Hurn is 8.7C. So the nights have been warmer this year than the days normally are in December. A total of 16 days in December had a minimum temperature in double figures at Hurn.

The average number of air frosts in December at Hurn is 12.2 days. This year - zero. Lowest temperature was 0.3C at 0600 on the 9th.

Totally and utterly amazing. I remember as a child being fascinated by the Rickmansworth (Herts) frost hollow but I don't know if there are recordings from that site anymore. Benson comes up from time to time and also a Surrey site- might be Redhill. Is Hurn unique because of its sandy soil insulation? Is it classed as a frost hollow the way the others are?

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My understanding is that it is the sandy soil at Hurn which is the main reason for the low minima. So not a frost hollow in the true sense of the phrase as the land is relatively flat at Hurn (hence why the airport is there). Redhill was a typical frost hollow, the name gives it away. But this site closed some time ago. Off the top of my head I can't recall the exact characteristics of Benson.

Correct. I've been there a few times and it's low lying but flat and like much of the New Forest area it has sandy soil

Never realised that was such a cold month.

What I do remember is the incessant rain!

Just a typo- 1992 was that cold. 1982 was something of nothing (10.1)

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It's hard to put this month in words because it's so off the scale. For me, it's beyond extraordinary. 

Unbelievable, climatologically ridiculous.....

The current CET mean minimum is warmer than any CET minimum recorded for April!

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Goodness me, you're right, Kev; and only 43 out of 138 Mays have been warmer- so it has been warmer by night than about two thirds of the Mays!

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Take out any indication that was December, never in a million years you would guess that was December!

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Final Hadley figure for December is 9.68C

So 1.6C above the previous December record of 8.1C. Needless to say no one in the competition got even close to this figure.

http://www.metoffice.gov.uk/hadobs/hadcet/cet_mean_2015

Here are the charts for December. Not much to add really to what has already been said in this thread. The numbers are truly astonishing. The record has been beaten by 1.6C. Warmest December for at least more than 350 years.

In the CET area the mean minimum and maximum temperature anomalies were very similar. However, the mean maximum was 1.8C above the previous record whereas the minimum was only 0.9C above the previous record.

Every single day in December was above average when looking at the maximum, minimum and mean temperature figures. 5 CET date records including 4 in a row.

Here is the CET record breakers page. We have only beaten two of the three high temperature records for December.

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

Highest maximum CET 15.3C 19/12/2015. Previous record 14.7C 23/12/1977

Highest minimum CET 11.9C 12/12/1994. Highest in 2015 was 11.0C on the 17th

Highest mean CET 13.1C 19/12/2015. Previous record 12.9C 12/12/1994

9.7

Warmer than any March, warmer than any November bar 1994, warmer than the previous November and that was the joint 3rd warmest November, the mean minimum warmer than any April mean minimum.

It is so off the scale, it's unreal, I feel like when the announcement was made this piece of music should be played with the timpanis banging after each record it has broken is made.

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December 2015 here had an average high of 11.7C and an average low of 6.1C. Overall mean 9.0C.

March 2012 had an average high of 13.5C and an average low of 2.2C (which is actually 0.3C below the LTA). Overall mean 7.8C.

I think it's going to be very hard or even impossible for March to record a higher mean, simply because in March, warm weather is almost always associated with high pressure, so warm days + cold nights, as opposed to December 2015's ridiculous 15C nights and 11C days.

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We have now set CET records for 7 of the 12 months in the period since 1994. This includes all months between July and December.

Thanks GW. I was on the understanding that March 2012 was also a record warm March??

It would be eresting to see if the record warmest May and June will ever be topped,both standing at 15.1c and 18.2c respectively.

March 2012 is only the 4th warmest on record. Warmest is 1957 at 9.2C. Forgot to mark that as red - will amend now.

Oldest monthly CET record still standing is February with 7.9C set in 1779

Not sure if this has been discussed but how does this December compare in a standard deviation kind of way to other record months? Or, I think I'm asking, how record is it?

I guess another way of looking at it is that a tm airstream persisted for much of the month. A tm airstream perhaps a degree warmer than we might expect? Or brought to us more directly from the far SW than is usual? We didn't smash maxima much we smashed persistence of airmass?

It's interesting reading other observation as that few other months could do this since we'd expect less cloud, the odd clear night, some cold night, in other months. I guess we might, next EN, see a November the same, one that averaged 11C now seem possible, or October and 14C plus. But, not later winter or spring months I guess.

I think it would be interesting to see the average highs and lows of these record months and whether excessive cloud influenced produced very mild nights rather than warm days. I'm sure March 2012 had the warmest average high of any March? Or maybe I am mistaken.

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Best way to see the ranked maxima and minima is at these links

http://www.metoffice.gov.uk/hadobs/hadcet/mly_cet_max_sort.txt

http://www.metoffice.gov.uk/hadobs/hadcet/mly_cet_min_sort.txt

In terms of maximum temperatures March 2012 equalled March 1957. But there were two warmer years - 1948 and 1938. In fact 1938 was a full degree warmer.

Annual CET competition - December update

Here are the final tables for the 2015 competition.

Congratulations to lanky who is our winner this year . It is only fitting really as he has been at the top of the table for 5 months this year, more than anyone else.

It was very tight though in the end as sussex snow magnet finished just 0.04C behind and Taylor1740 just 0.24C behind.

Our leader last month John S2 dropped to 7th this month. He does have the distinction of being the only person to be in the top 10 in the table in every month during 2015.

A number of people in the top 10 finished at their highest position of the year including Darren S, nouska and redmoons.

Several large climbers throughout the table including Surrey John, moonmin75, cowman and Gavin P all going in the right direction. It is all relative of course as nobody made a close prediction this month but some were closer than others.

Worth noting that if you had predicted the 1981-2010 mean every month throughout the year your error would have been 12.89C. So that puts the final table into perspective.

Thank you to everyone for taking part in another hard fought competition this year. Lets see what 2016 brings. Happy New Year to everyone.

Monthly positions

Monthly prediction errors

Yellow shading indicates an error of 0.25C or less. Orange shading means the person did not make a prediction in that month so an error was automatically calculated in accordance with the competition rules.

 

 

Congratulations, though, on winning the December round.

 

Has there ever been a month before where the winning prediction was out by more than two degrees?