Moisture I think but do not quote me! :)
But the freezer keeps it perfect.
Setting up a honey bee colony is harder then people think BTW. If you are just interested in bees for your plants then mason bees are the way to go. No honey but much less work.
My husband built a bee wagon so we can easily wheel the hive around and with slotted frames rather then stacking ones.
Much easier on the (getting progressively older) back.
Having your own beehive sounds great. What a wonderful prepper solution, instead of storing honey. If you feel like explaining how to set up a hive I’m sure everyone would be very interested in it. I know I am. And especially, how do you get the honey out and filter it from .....well , bee parts.
I’m looking into eventually adding some horizontal hives to my farm. They have the advantage of not needing to lift a heavy super. You can just take one frame at a time, as needed.