The first two weeks of January have seen very cold air coming from Russia towards Central-Eastern Europe, with lot of snow especially in S. Germany, Austria (more than 2 metres in the Alpine region) and the Balkans. Also in Greece and S. italy snow has fallen, at sea levels at times.
In northwestern Europe instead, and especially between France, the UK and the N. Atlantic, a strong high-pressure ridge has caused settled conditions for several consecutive days, causing also very warm air towards these areas and Scandinavia.
I have analysed and plotted the daily average temperatures in 17 countries (cities) and compared the results. This analysis is simply focused on considering the main cities, thus it is not a detailed analysis for each country.
The results (Figure1) show that in S. Europe (especially between Italy and the Balkans) the daily average temperatures have been lower than in central-northern Europe.
We can see how Rome and Istanbul observed similar or lower temperatures than London, Paris and Amsterdam (to cite a few). In addition, it is impressive to see that Reykjavik has observed a very similar mean temperature to the cities in southern Europe.
Also the Balkans have observed temperatures lower than in northern Europe, with Bucharest colder than Stockholm and observing temperatures very similar to Helsinki.
However, not all southern Europe has observed low temperatures; the Iberian pensinsula has seen warmer conditions (though with temperatures close to their climatological average), with Lisbon the warmest capital so far. This is due to the frequent flow of warm air coming from the Tropics caused by the high-pressure ridge set (since December) between W Europe and the Atlantic.
In E. Europe (Warsaw, Moscow) the lowest temperatures have been observed (which is also in accordance to their climate); these areas where directly influenced by the polar continental air coming from E/NE Russia throughout the whole period.
If we look at the daily temperature anomaly (Figure2) computed respect to the climatological average (1981-2010), we can see how Reykjavik has observed the highest values (almost +5 °C; the daily mean average temperature in January for the Icelandic city is 0 °C).
Overall, all the area from France to Scandinavia and Iceland has seen warmer temperatures, instead E Europe and S/SE Europe have experienced a colder weather.
In conclusion, we can say that the new year has brought cold weather in the southern and eastern part of the continent (with snow in numerous and unusual areas); instead, the western and nothern areas (especially the countries along the N Atlantic coast) are still experiencing mild conditions (as occurred also in December).