Lots of people have claimed it will be and they could be correct, but there are two obvious problems:
1. The year is not over yet.
2. "Hottest year ever" is not well defined. There are a number of different published temperature series, calculated in different ways. "Hottest year" looks a lot less striking if it turns out to be true by only one measure out of five or six.
The series I mostly use in climate arguments is one from NASA
, not because I have any reason to think it better than others but because it is one that I found conveniently webbed as numbers, not just as a graph. It shows 2010 as the hottest year so far. Just for fun, I added up the temperatures for the first eleven months of 2010 and 2014. Currently, 2010 is ahead by about .01 degree C.
But December of 2010 was relatively cool, so it would not be surprising if 2014 inched past the record in its final month. Or not.