Chilly ghosts--can they actually freeze a Sim to death??

My sims just survived their first winter (yay). As long as they were dressed in their winter clothes at all times, they were fine. If they were outdoors in regular clothes, then they'd get the uncomfortable moodlet. I just learned about the thermostat, so haven't had a chance to make use of it yet. I only got the notification that my sim was freezing to death once (the warning), and I changed his clothes and got him indoors immediately and he warmed up quickly.