I have a small water garden outside my kitchen window and use it to judge how cold it really is and how long it has been cold. Well, for southeast Virginia it has been pretty cold! The spitter in the photo below has had ice forming around it for the last few days. The water stream is actually now deflected by the ice to the left (behind the ice block). When it gets like this I start worrying a little about the bees, but not too much. Compared to what folks up north work with, it is not so bad here. The weather is staying cold until at least January 8th, when it will get up to about 50. I'll check some hives then and add winter patties as needed (I make them myself).
I use a thermal imaging camera to check on hives in the winter. These photos are a little blurry, given the lack of ambient light, but they quite nicely show the winter cluster of this small hive. There is a clear six degree temperature differential near and away from the cluster.
For the winter I place dry sugar on the inner cover as emergency food for my bees. Many folks put it on the top bar, using newspaper to hold it. I've found putting it on the inner cover is easier and just as effective. The second photo is a cluster that was checking me out as I removed a box and lowered the inner cover. I was very late getting this hive ready for winter due to a longer vacation.