Boardgame storage in the attic

I'm making a boardgame storage in the attic. Something simple, a nice long wall of kallaxes or something like that.

One thing that worries me is that the attic is not climate controlled. How do I prevent mold from affecting my boardgames? Do I just place a dehumidifier and make sure the shelves are ventilated? Is there more to it?

I doubt temperatures drop below freezing in winter up there so temperature throughout the year will be 5-35C most of the time if I had to guess.