Boise, Idaho
Two days ago, it was unseasonably warm.
In fact, it was nearly 80 degrees in most of the Treasure Valley.
Then in the middle of the night, a cold front started moving through.
The 61 degree high for yesterday was reached at midnight. The low for the morning was reached at six bottoming out at 39.
It snowed several times during the day, and between the wind chill and humidity it felt bitterly cold!
How cold was it? I’m not sure. But it felt this cold:

I actually took this picture many years ago in Fallon during a pogonip.
Pogonip is a type of freezing fog that occurs when liquid fog droplets freeze to surfaces. This is very common on mountain tops which are exposed to low clouds. It is equivalent to freezing rain, and essentially the same as the ice that forms inside a freezer.
In the western United States, freezing fog may be referred to as pogonip. It occurs commonly during cold winter spells, usually in deep mountain valleys. The word pogonip is derived from the Shoshone word paγi̵nappi̵h, which means “cloud”.
In The Old Farmer’s Almanac, in the calendar for December, the phrase “Beware the Pogonip” regularly appears. In his anthology Smoke Bellew, Jack London described a pogonip which surrounded the main characters, killing one of them.
I haven’t seen pogonip in Boise, but it felt cold enough for it yesterday…