I'd have to agree with some of the others that the coldest I've ever been has been duck hunting over decoys. A hunt in the Ruby Marshes was possibly the worst. We were hunting a pond/channel thru the bull rushes that was open only because of a current from a nearby canal and a 30pmh crosswind. Without any ground to stand on, we were standing waist deep behind the canoe wedged into the bullrush. Our two labs were in the canoe, under decoy bags. One of us laid his gun down for a few minutes on the bags and when picked up was frozen to the bag (God bless the 870 - it always goes bang!).
I finally connected on a crossing pintail; both dogs jumped out of the canoe, swam like arrows towards the dead duck for about 20 yards and then in what looked like a correographed and planned action turned hard left 180 degrees and returned to the canoe. These were both seasoned duck dogs so when they threw in the towel we listened & did the same. Still wish I had had that sprig mounted - maybe in a block of ice!
I don't know the temperature, but I remember a very cold opening day in Michigan in the late '70's. Everything covered in frost, snow squeaking under your boots, finger-numbing cold all morning long that you just couldn't get away from.
When we met at the vehicles at noon, my elderly uncle with poor circulation was so cold that he could barely stand up. When he started to unload his rifle, he began staggering around like a drunk. He had a rifle that had to have the safety off to open the bolt, and the rest of us were all dodging to stay away from the direction of the muzzle, which he was swinging all over the place trying to keep his balance.
It was -15* F the morning I started up the mountain the day I shot my Mountain Goat. I skinned my billy where he fell for a full mount. My hands got so cold that I pulled the goat's skin over my hands to retain some of the goat's body heat while I skinned most of the body.
But the coldest hunt I can remember was one day I went with a friend who had a late season elk hunt in the upper Gallatin River area in SW Montana. The thermometer read -42* F that day. It was a two day hunt, and we didn't go back the second day.
The coldest I've actually hunted was just below ZERO. I can't say that I enjoy being out in that kind of weather. I sat in a duck blind for a few hours one morning with the temps in the single digits and I hated it. When you're not out walking around, it's easy to get really cold. I'm fortunate to hunt an area that seldom gets below the teens during the deer hunt. Teens in the early morning and upper 40's during the afternoon. That's just about perfect weather for deer hunting. Hang and skin an animal and it doesn't take too long to cool them out.
But high on my bucket list is a musk ox hunt in the far north. I know it's COLD on those hunts but I'd be well prepared before venturing out.
I've spent countless hours either on my hands and knees or bent over, messing up my back, looking for blood. One such instance I remember most was a hog hunt a few years ago in Mississippi. I had never shot a hog so when I poked a hole in this guy; I was determined to find him. Wearing snake leggings, I crawled on my hands and knees through the briars and the brambles and bushes where a rabbit wouldn't go. I found a spot of blood here and there but never the pig. And lucky for me, I didn't find...