On Friday, 1 January 2016 11:16:18 UTC, John Hall wrote:
In message , Dave Cornwell
writes
Summary for December 2015

Temperature (°C):

Mean (min+max) 10.8 (+5.7)

I suspect that that is actually higher than your mean for the calendar
year 2010, which is quite remarkable.
--
John Hall


I doubt if that's quite true if this place is anything to go by though it's not far off.
December mean here was 10.2°(+5.6) but the annual mean was 10.8° (+0.6). One remarkable statistic is the uniformity of max's during the month. The highest was 14.8°, the lowest 9.1° and the standard deviation of the daily figures, something I evaluate for each month, was only 1.27° or about one-third of its normal value for a winter month.

Tudor Hughes, Warlingham, NE Surrey, 557 ft, 169 m.