Being cold in and of itself should not cause issues. Rapid temperature and humidity change can be a real problem. Don't bring them inside and walk away or you will induce a rusting problem. Cold metal brought into a warm environment will condense any moisture in the air like a glass of ice water. If you don't remove metal from stock, dry it out and let it stabilize and re-oil, you will end up with issues.
When on the farm, the truck guns stayed in the truck. Carrying them inside and outside would get them rusting quick.
