If you can find a Wolf Suit or Dinosaur Suit consider wearing those. You’ll be weird, but you’ll be warm. If you want them to be armored just pad them with Kevlar, though watch out for the encumbrance as it’s very severe across your entire body.
Another way to get warm is to find a bed that’s not in a vehicle. If you put a bunch of blankets or clothes on top of the bed and then sleep in it for any amount of time (even the 30 minute shitty sleeps if you’re not tired) it will instantly make your temperature comfortable no matter what.
Speaking of vehicles, if you’re inside of a powered vehicle and every space around you in a 3x3 have roof and floor tiles on them, the vehicle will trend your temperature towards being comfortable, making it near-impossible to freeze to death inside of one.