Why not insulate them . or even drop a heater small lizard type
Further north ie up in the really cold states and Canada they do wrap the hives, using roofing tar paper, Some put insulation sheets around the hives.
Here our temperatures are too psychotic, up and down. Warm up until the end of December, wrapped they would have been too warm, ie flying more than they already did, looking for food that is not there.
And now if wrapped, my hives are full sun, they would be out flying when it is in the 20's thinking it is warm enough to find food. They die unable to get back to the hives. I am currently finding a bunch of dead bees, on the deck on the hot tub near the ponds. They have flow out, sun warm up, could not make it back to the hive.
This is our coldest winter since 2017 or so, after we had our warmest December in years. The bees ate a ton of food in December, they flew every day looking for nectar, find none go back and eat to stay alive. The activity was like a summer day.
The winter bees live almost 5 months, the summer bees live around 32 days. Mainly due to flying looking for food. Winter bees are a bit bigger and have more fat cells. Recently I am finding a lot of dead bees at the bottoms of the hives, most likely due to flying so much in December.
Right now all I can do is treat for mites, make sure they all have sugar blocks on top of the hives and wait for a 60plus temperature day to see how big the cluster is, see if they might make it.