Gameplay Idea #2: Weather and Climate

I'm sure I'm wrong in this, but I don't believe that there are any roguelikes out there that incorporate weather and climate into their world model. Even indoors and underground there could be great scope for dynamic climate. And of course, not all climate could be caused by mere atmospheric phenomena. This sort of thing springs to mind:

"At the beginning of an elemental invasion, portals will open to the Elemental Plane and invaders will begin to pass through. Thus, during an invasion, you will find two to three times as many elementals in the area, usually slightly higher in level than the standard ones found there.

At some point during the invasion, the elemental leader will appear and begin yelling challenges that can be heard by all in the area. While the elemental leaders are alive, more and more invaders will spawn. Once the leader has been destroyed, no new invaders will appear, although those already present will remain until they are killed. "

Or how about a dynamic almost dungeon-wide storm of this? In a multiverse of magic, the possibilities are endless.