I spent a Thanksgiving climbing on the East Side a few years (plus or minus a couple) back. It was cold. Very cold. Water bottles freezing sold in our car during the night cold.
We ran into some climbers from Kentucky that didn't seem to know how they got to the Pinnacles. No guidebook, just climbing on random bolts until they fell. They were tying-in with square knots and employing lots of creative hands-free belay styles. My partner and I gave them a lesson on knots and let them see our guidebook. (Actually, my partner did this. I suggested that we get the hell out of there before we had to help with an evac, but he's a better man than I)
What do the two have in common?
They were staying at the campsite next to us. One of them was sleeping in a square sleeping bag in the open bed of his truck and the other was sleeping in a mesh hammock with only a blanket. (They didn't think California was going to cold) We shared a beer or two with them and let them know how cold it was the night before and they told us that they could handle the cold so we retreating to our tent. Later as it became more and more bitterly cold, we could hear them cursing at each other and mother nature in general until they both spent the night in the cab of the truck, running the engine to warm themselves on and off throughout the night.
By the time we ventured out of our bags, they had packed up and hightailed out of there.