The Outside Air Temperature (OAT) can be between -50C & -70C. At jet cruise speeds there's a rise of about 30C so the temperature at some parts of the aircraft skin will be -20C to -50C - still pretty cold.
At the doors the aircraft skin turns in to meet the floor forming a continuous heat conductor from the cabin at +22C
to THE OUTSIDE at -50C.
Some aeroplanes have electrically heated underfloor mats in the door area to combat this problem for passenger comfort - I guess yours didn't.
Problems sometimes occur with ice forming on the inside of the uninsulated skin which melts on descent and drips all over us