I live in San Diego and we are experiencing a lot of cold as well, at night we go all the way down to the 60s, it is freezing!!!!!!
Well now that you are mad at me, let me explain that I like to go to the mountains every year to ski, and my Porsche cayenne does this really weird things at cold temperature, warnings and ghost alerts.
As far as I know with cold temperatures sensors become more sensitive, it could be just a glitch due to the unusual cold.
There is a way to fix it, park the car, pack your bags and come south and don't come back until May (you know you want to)