The coldest I have ever been was in the back seat of a Morris Minor travelling through Amarillo in December 1960.
For those of you in the U.S., the Morris minor heater was the size of a shoebox and tried to warm the feet of the person riding shotgun.
A bit of trivia: The first (only?) time I ever evaded and ran from police was on that trip. My turn to drive, to warm up, and with four people on board, the little beast would almost maintain 80MPH in flat central Texas. Pitch black, no traffic anywhere, I saw a small town far ahead. Closer in, there was the local mountie in someone's driveway. Seeing there was some kind of statue dead center in the town square, I could see the mountie's head lights just turning on to the highway in the mirror. Fortunately just before reporting to the USAF in 1959, a friend had bought a new '59 Morris Minor so all of us back then knew how it handled. I kept the pedal down, made quick right, left, right around the statue back to the straight and level. When I next saw lights in the mirror they were very faint & close together and soon turned around.
Sorry for the story, the cold made me think of it.