Every time it snows, deniers claim "see, there's no global warming" and believers say "weather is not climate!" The summary of this article then uses the past three months and declares it proof of climate change.
I realize that the actual article is more subtle, but I believe the point OP is making was that if you don't want "Polar Vortex" to be used as an argument against climate change, you probably shouldn't use "heat wave" as an argument in favor.
Taken as a whole, the trend is clear. Leading with a headline "last three months hottest ever" is only going to remind people in DC that they just experienced the coldest winter in 20 years and the most snow ever recorded.