Dan and I occasionally bicker about this. If it's December, it's winter as far as I'm concerned. I don't care that the season doesn't officially start until later in the month. It's been a little on the chilly side here, getting down in the 40s overnight. We don't even have heat in our bedroom!
Brrr... It is what a good chunk of our winter has looked like as well. Which, quite frankly, is odd.