It has often rained, but a few years back it was torrential. We were lucky enough to duck into the BBQ seating area, and since we were hungry, we ate. The thunder, lightning, and rain gushing continued, and we had no choice but to wait it out. I thought there would surely be trees down when it was done, but there were not. And yet, when it was done, we rode the rest of the rides in the park. I think the only things we missed were the carousel and the balloons.
Other times, we've gotten those great Ozarks rains - just enough to be too much, and never ending. Those times were not as much fun.