Bump - and amazed I actually found something via Search on here. Had not been able to put my finger on it until recently, but weather is one of the immersive aspects that is desperately needed. Sandstorm on Mars was the one that came to mind first, as well. Acid rain on Venus would be good, as well. Not really much going on where the Moon is involved, and there are no remnants of dead vegetation, like the tree trunks on Mars. Hell, even a "solar storm" that would cause some sort of borealis-effect and maybe throw some static in your HUD?