It's not, taken in complete isolation, evidence for global warming. It's an example of it. When people call something evidence in this sense, they mean it collo

It's not, taken in complete isolation, evidence for global warming. It's an example of it. When people call something evidence in this sense, they mean it colloquially - that it is an exemplar of an overall body of evidence that points in a particular direction. The record cold month is part of the same body of evidence that, overall, points to the existence of global warming, but it isn't an exemplar of that evidence, so it doesn't get called "evidence" colloquially. Similarly, an individual fossil might be called evidence of evolution, but nobody thinks you should take this one fossil as a knockdown argument that evolution is real. On the other hand, when a strange fossil that's anomalous with the rest of the record is uncovered, a creationist might call this "evidence that evolution is false", but just as in the record cold month case, it's correct to point out that you shouldn't be looking at individual fossils. So what's happening here is that people are using the word "evidence" in a rather casual manner. Properly, what we're talking about here is an example, and in this case it's a very pertinent example because people have been given a concrete picture of what the world might look like on a regular basis in the near future. (Obviously there are some members of the public who really do think a single month is proof of global warming, or vice versa, but I'm trying not to strawman anyone here.)