Here are the final charts for the year. It looked at one point like the CET would finish below average and below 10C. But in the end the incredible warmth at the end of the year pushed us quite a bit above average.
The CET started December at 10.36C and finished at 10.29C so it hardly dropped at all in December. Usually the figure drops rapidly in the final month.
The competition winner is Neil M who predicted 10.27C.
Hadley show the final figure as 10.31C on this page http://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat
But that only takes the data to one decimal and does not allow for the fact that different months have different numbers of days so a straight mean across the 12 months is not totally accurate. The correct figure taking a mean of all the daily CETs is 10.29C.
Second place goes to domma with a prediction of 10.32C