Humidity is definitely of huge concern here, but thank goodness I can switch between work and home!
At home it can get pretty humid in my office, which is on a third floor. I close it off during the day and, with the A/C off, it can get pretty stuffy. I have all kinds of valuables there, so as soon as I get home I open it to let the cool air in.
At work, where the only board I have is my Realforce, is perfectly air conditioned in the summer and comfortably heated in the winter. I really ought to move all my boards there...