Snow stopped yesterday afternoon. It is now -8F and still dropping.
I had a piece of cardboard which I used to absorb solvent (about 3 ounces) when I was cleaning something. This solvent is sort of dangerous and honestly, the best way to dispose of it is to burn it. If it evaporates, it can lead to ozone issues etc.
I laid the cardboard on the snow and lit it on fire.
The snow never melted! The snow acted like stone.
That is when you know it is cold, when fire on ice, ice wins!