Howdy,
Yeah, I would take that radio inside each night in really cold weather. I don't think very many amateur radios meet MIL STD 810 for temp.
Congrats on your son going to UPT!! You must be pretty proud! He'll be "under the gun" for about a year but he'll love it! I went to Vance AFB, Ok for UPT in 1980 and it was a LOT of fun! (retired from USAF/USAFR in 2004)
73/Rick