You can describe something that is unpleasantly cool, damp, and clammy as dank. If you have ever visited a cave or unfinished basement, you know how a dank place feels. Yuck.
The adjective dank is often used to describe places that would have moist or damp walls. A dank cave can provide hundreds of bats shelter, but you probably wouldn't want to visit them. Tunnels can also be choice dank locations: "The tunnel under the harbor was always dank, and the workers constantly had to battle mold and lichen on the tile walls." One way to remember dank's meaning is to think of dark since they share three letters and seem to go together; a dank place is often a dark one as well.