So I have everything set up perfectly for my snake rack, EXCEPT a hygrometer. My question is, how so I measure humidity of 6 different tubs? Do I put a digital hygrometer in each tub? or do I not worry about it, since they have large water bowls and cypress mulch?

I am accustomed to measure only one tank, with one hygrometer in the tank. What is the simplest way to measure humidity of the tubs in my rack?