He mentioned the “Rule of 3’s: .... air, water, food. Here’s the one I live by: 3 hours without shelter, 3 days without water, 3 weeks without food. Good friend of mine is with SAR .... when I asked her from her experience what most folks die from, her answer was ‘exposure/injuries’. Hypothermia kills in a hurry ..... I’ve had to deal with it before, personally & with other folks so I know how it works and it’s not something you want to have to face, if at all possible.
US Army Survival Guide.....free download for Andorids:
https://play.google.com/store/apps/details?id=com.androidtrainer.survive&hl=en
The real show stopper is water. And yes, I would drink my own pee as a last resort.
Even with proper clothing, in a cold environment if you don't have a food supply you're going to be in trouble a lot sooner than 3 weeks.
The question is of course utterly dependent on the environment. Summer desert is as unlike winter mountains as can be imagined. Either will kill you really quick if you're not prepared.
Speaking of SAR about 30 years ago wife and I walked out to National Park headquarters after an early spring storm, with our 1.5 year old little girl.
SAR was mounting up in the parking lot, so I walked over to see if I could help. Turns out there was a couple lost in the mountains with a baby...
Friend of ours panicked. But we were prepared and never in any danger.
That said - I spent last weekend out in 15 deg weather all day (10hrs) properly dressed
I had no rain gear back then in my poor days
You left out fire.
And fire comes first. It’s far more difficult to create, than Shelter.
Once you have fire, you can heat shelter, and boil water.