Okay, I have two individuals, male and female, who are exiled and attempting to get... somewhere. Winter is approaching and it becomes too hard to travel overland. The area does/will experience snowfall. They decide to winter over in some kind of enclosure. Here's my question.
How far do you have to get into a cave for it to become the 'ambient' temperature of ~60 degrees Fahrenheit? Would it matter if said cave was exposed on a hillside or in a sinkhole? (I have yet to decide if this terrain will be igneous/metamorphic rock or some sort of carbonate; carbonates lend themselve to caves better, but I am not sold on the accessibility of my fictitious cave. Besides, such caves are typically formed by water, which would be BAD in the wintertime.)
What about some sort of abandoned tree-stump? (Assume these are great big redwood sized trees.) If they fashioned some sort of hole-flap, would that be better? Could that change the depth I would have to go to with a regular cave?
Thanks in advance!