Bottom line - the defenders of Global Warming are still on weak ground.
Another major problem with this explanation is the summers. The same years that we had bone-chilling winters, we had record hot summers. A chart of days over 100 would resemble the one of days below 0. There would be a few leading up to some really hot summers in the early 1980s then a cooling. For the last couple of decades, we have not exceeded 100 in most summers.
It's a very glib explanation but there are some major problems. The graph of cold days only goes back to to 1970. Even with that it is clear that the late 1970s and early 1980s were anomalous. Winters got a lot colder then they warmed up again. I remember the 1960s and days below zero were rare. A chart showing a longer period would show that there are naturally occurring warm and cold period. I'm also old enough to remember that the reason for those cold winters in the 1980s was the same reason that this winter was cold - Canadian air got deflected further south than usual.
One cold January in the US does not prove anything one way or the other about Global Warming. It does have a lot of people wondering about the more extreme predictions. Al Gore had predicted that well before now the world would have warmed so much that Washington DC would never see another snowfall. This was demonstrably wrong.One flaw in the warming theory is the 15 year pause in warming. Eugene Robinson recently published an answer for that. If you just discount 1998 as an outlier then everything is fine (except a closer reading of the paper in question calls for ignoring three years out of 15 instead of just one). Who is actually cherry-picking that data when you have to throw out yeas of actual weather to prove a model?
A side-note: I doubt that any true believer in 1998 said, "This year is an outlier. You can't use it to prove Global Warming."
Then there is this which explains away the cold winter. According to the embedded cartoon, winters used to be really cold then they warmed up because of Global Warming. What used to be normal now feels cold to us.