There are all sorts of GUI defects with the weather interface. Sometimes you will see a cloud layer change from Clear to Overcast depending on what you have its coverage set to, most of the time it does not. You can also find a cloud layer will not even render correctly, and it has a lot to do with their order. Dragging a cloud layer above another, for example, can “break” them, and you have to reset the weather preset to restore its functionality.
Fun to play with. Here was a preset I created that gave pleasing clouds.
