The BBC (among other news) reported that the polar temperature on December 25th 2016 could break all records by a staggering 20 degrees celsius above the average for that time of the year.
Some would argue that this is merely an unusually warm winter. Nothing more than 'weather'. This may be the case, if examined on its own, however 2016 has broken all current records by some margin with each of the last 15 or so months (by my last count - I may be incorrect here): See image.
Other people refer to the fact that the climate of the Earth is continually going through trends of cooling and warming. One thing about that particular argument is that these trends tend to take centuries and not years/decades.
Yet more people refer to record breaking cold weather in other parts of the world. The data that is presented is a global average. its measured in a consistent way in order to have a minimal local interference as possible. Could this data be questioned? Sure. Could it be wrong? Sure. However, there is much anecdotal and observable evidence that also supports the figures: melting of permafrost, recession of glaciers, shrinking of ice caps, alterations of migratory patterns, extended lives of insects (due to milder winters).
Of course I could still be incorrect. After all, science is built on the mistakes of those that have come before. One thing about a theory is that it can not be definitively proved correct so if you ask me to guarantee my argument, I simply cannot.