An issue that must be pointed out is that despite the climate seeming to have got colder, we're still well below our 'fair share' of extremely cold months. By law of averages every year should, statistically speaking, have one month within the 29 coldest CET months (355/12), for that that month of course. So in the last five years, only two have: December 2010 was second coldest and March 2013 should be within the top 30 coldest if it has a CET of 3.2c or less. Before this supposed shift, we have to wait until February 1986 to find a month that was similarly exceptional, when there actually should have been 25 such months.
On the other hand, we've seen 13 months in the top 29 most warm: January 2007, February 2008 and 2011, March 2012, April 2007, 2009 and 2011, May 2008, September 2011, October 2009 and 2011, and November 2009 and 2011. This is as opposed to our 'quota' of 5.