Geert Jan van Oldenburgh of KNMI has prepared an analysis "Klimaat 2010: a winter of extremes - Cold in Europa, Siberia and the US, but above normal globally".
His summary is: From Ireland to Siberia the winter of 2010 was colder than usual. The winter temperatures in the eastern half of the United States were also below normal. However, on Greenland and in north-eastern Canada it was much less cold than normal in winter and the Middle East was also milder. This pattern was caused by a well-know climate mode of variability: the Arctic Oscillation (AO), also referred to as the Northern Annular Mode. The Arctic Oscillation had its largest negative excursion since the beginning of observations in 1900. The net effect on the global mean temperature was close to zero: the cold air brought south to Siberia, Europe and the eastern US was compensated by warm air going north into other regions. The global mean temperature was in fact near record high, pushed up by the combination of the slow trend and the effects of the 2009/2010 El Niño.
Full text: http://www.knmi.nl/cms/content/78168/2010_a_winter_of_extremes