Christmas and winter

My lovely wife got me a stethoscope for Chtistmas! We used it yesterday - the idea is that you hold it against the hive wall and listen. We could hear some short buzzes and then picked up more of a low background hum. It was cool.
This December has been the coldest on record with local daytime temperatures at or below freezing for several weeks now. Cold is not a problem to their survival right now but I wonder if they are using more stores as they consume honey for energy to keep warm. They may need that fondant earlier this winter.