OK, I just froze my butt off checking my hives. I had to pry the top off the PV=nRT nuc, it was frozen solid to the hive. We’ve been below 32F (0C) for quite some time now. My little IR thermometer read 28F outside (-2C) the hive and 55F inside the hive. As you can see from my earlier post, the bees really haven’t moved much.
My full sized super insulated hives with top entrances (9mm x 25mm) were reading 50 to 55F at the top entrances.
Like you, my foam hives have the insulation capability to be much warmer than they are. I think it comes down to the temperature at which bees cluster. Below that temperature they are going to cluster and make some heat, above that temperature they break cluster and don’t generate heat. That being the case, I’m not expecting my hives to get above 60F/16C the rest of the winter unless there is some solar gain or until they start brooding. Once they start brooding, they should be making heat all the time and that’s when all the insulation will start bumping the inside temps into the 70s or 80s.