I don’t post here often, but happened to stumble upon this just now. Agree with what you said—it has been cloudy and windy (and snowy) with the coldest air masses—not great for rad cooling. I also agree with Bluewave on how warm Canada has been generally in recent years. If you look at most recent Decembers, with the exception of last year they have been headed in a warmer direction.
The locals here talk about how fast a start it has been with snow, but we haven’t had any truly cold nights relative to what the area can get (not that I’m a local, I’m new to the area).
It’s been a cold month overall however. The airport is -3.3° as of 11/17. Normal hi/lo for today is 41/21. In the village we had a low today of 24…but we’re currently at 27° and will struggle to hit freezing again.