It's amazing what exterior water management, or lack of, can do. I got home from down south in early spring, and after the first good rain, the humidity in my crawl space spiked, and stayed that way, which is pretty unusual. I then figured out that the gutters had gotten clogged (again) with leaves, and water was overflowing, evenly saturating the concrete wall. Fifteen minutes with the step ladder, and leaf blower, and my crawl moisture started to go away.