Looking at the daily data on Hadley, yesterday's mean was 15.0°C. Nothing in November 1994 came near that- and actually the day before was above 14 and I suspect today will be at least that.
Scrolling through since 1980, there have been no other November days with a CET mean of 15, only 5 others of 14+, and 17 of 13+.
Not sure about pre-1980 but this could be a record.
(Worth noting perhaps that in 2014 it was 16.8 on 31st October- such a close miss. And in December 2015 there was 13.1 on 19th.)
Originally Posted by: Bertwhistle