cold water, not cold weather, really is the issue up here. the cold sucks the heat out of everything below the waterline. the temp in the salon can be 20 degrees (C), but the settee is cold and the sole is cold. so cold that even with slippers on, while standing cooking something for dinner you can feel the heat seep out of the bottom of your feet. the v berth is the same thing - even with 6" of foam underneath, the heat just drains away.
i started wearing shoes all day because of the cold sole and wound up with athlete's foot
even if we had ice at these latitudes, there would be a ring of open water around my boat from all the heat loss