Zangarmarsh has rain as well, but I can't think of any other zone in Outland that has weather effects that come and go. Sure, some zones have Infernal rains and such inside and outside of them, but that isn't really the same. It's a constant, it's static. When you go to that zone, it will be there 100% of the time. Azeroth's weather wasn't like that. After it was added, of course. It might be raining in Stranglethorn, it might be sunshine from horizon to horizon. When it was raining, the zone had an entirely different feel. You were doing the same things, but it just felt different.
I brought this up with some friends of mine a few times before, and we tried to think it through with logic at first. You know, the atmosphere is different, so maybe other zones in Outland can't rain. It's an alien world, so who knows? Even if you play the 'alien world = no rain' card, I think there are some awesome weather-related things you can do. Read on for my thoughts on the matter!
Here's some examples of what I think could have been done in Outland.
- Shadowmoon Valley: Obviously it isn't going to rain in this zone. There is a massive volcano in the center of the zone, though. Why doesn't it erupt now and then, or at least become a little more active? Rain fire and brimstone on the zone, dust it with some ash. Maybe toss in some occasional screen shake.
- Netherstorm: Again, not a typical zone. You're not going to see rain and snow here. It's full of unstable mana, though, and it's floating in chunks in the Twisting Nether. What about an 'Arcane Tempest'? Psychedelic streams of neon color flowing through the zone, visible vortexes floating around. Netherstorm is very purple, so wispy trails of other trippy colors would definitely give this zone a feel of 'what the heck is going on here?' The zone has some neat stuff already, but could use more visuals to accompany it.
- Terokkar Forest: Rain would be really good here, maybe accompanied by strong winds. Lots of loose leaves blowing by. Perhaps the calls of frightened birds(and arakkoa) carried on the wind? Could be rather spooky, considering that zone is already a bit dark in the forested regions.
- Anywhere super creepy: Raining blood. You know you dig it.