rdy-b
your suggestion
'ITS colder at night so the bees have to generate more heat it is the heat from the cluster that is fluxing the humidity-'
I agree, at night when the outside temp decreases , the temp within the beehive increases, this can only happen if the metabolism of the bees increases, perhaps in response the decrease in the outside temp. one of the byproducts of the consumption of honey is water vapor, hence the increase in %humidity in conjunction with the increase in temp; I think?