Up here in maine we have been haveing days in the low 50's and at night its been in the low 40's. I have two hives which are both top entrance hives and are built exactly the same. With the temps we have been having I've noticed that one of them keeps building up a good amout of moisture on the cover and it has been dripping a little onto the frames,now with it being a top entrance hive im kind of confused on why im having moisture problems...... So far i have'nt had any problems with moisture in my other hive knock on wood. I have solid bottom boards on both hives right now, Ive thought about putting screen bottom boards on to hopfully help with the problem. What do you guys think?
I think maybe you have more bees in one hive then the other.
Put a couple of pennies in the corners of the wet hive, just under the inner cover to increase the ventilation some. That should help. Even if it's just on one end.