Using a rainy day in PA scenario where we left the shelter in the AM and it immediately started pouring and continued pouring for 4 hours, good luck on starting a fire unless undercover. Even if I was to build a fire under an overhang at a shelter, any fuel in the woods would be saturated. I am aware of most of the tricks out there on how to make dry wood when there is none readily available but when the woods are wet even those tricks can prove elusive. I once spent about 2 hours in the rain with a bunch of senior level boy scouts trying all the tricks and it was a major effort to get a fire that might be regarded as something to warm up to. Sure I can use a trioxane bar to get a quick fire but once the bar is gone unless I was really prepared, I may not have a fire that lasts. Add in diminished metal capacity from mild hypothermia and the odds get worse. Give me dry conditions and its a relative no brainer but generally hypothermia is a cold and wet/damp scenario unless winds are in the extreme range.