My daughter, (she grew up in north Idaho), shared her personal basic cold weather gear, glove liners, wool socks, etc., during her winter TBS (Marines). She was amazed at how training was not prepared or understood how to deal with cold weather.
Same thing I saw. There were guys who had done camping, etc., who were miles ahead of guys who had never done that. And assuming you're referring to "the" TBS in Quantico, no classes on that there either.
That really bad night when it was cold/raining, and we were eventually allowed to bed down, I ended up rigging a lean-to using my poncho, dug a little trench around it, etc., and did fine. But some city guys just walked around all night to stay warm. I tried to tell some of them what to do but they were kind of miserable by that point.
Learn the hard way, I guess.