A static theme. Powers up, speeds up, or boosts electric moves/Pokemon. Certain Pokemon can have an ability that creates static in the air. Easy.
Nightfall. Boosts dark or ghost types. Give a Pokemon a Nightfall ability and make it similar to rain teams. Dark needs some serious juice. --- The Rated Lar Superstar. Dallas Mavericks Fan. Clan High Five! http://i.imgur.com/WvefuGH.jpg?1
Eh... electric's kinda already covered by Rain, but... if there was a static-in-the-air thing, it could be primarily flying and lightning could coast on the two of them as its "effect". Dark... well, the Night Fog thing I'm a huge fan of (other topic), maybe if you gave some effects though? --- "The point of war is not to die for your country. It's to make the enemy die for his."
And a canyon is certainly a good weather effect name. ... I'd have just had it be affected by Hail. Refraction of sound in a blizzard, etc. --- "The point of war is not to die for your country. It's to make the enemy die for his."
Night fog could lower accuracy for all moves but dark type. Dark type moves would always hit. Maybe have a negative effect on psychic and a positive effect for Ghost.
There should be a move that removes weather conditions. Like the move version of airlock --- "Hello, um, you..." That akward moment where, after talking to someone every day, you still don't remember their name.
Powers up Dark-type moves. Halves power of Fairy-type moves. All non-Dark/Ghost/Psychic moves get 10% accuracy drop. Spongebob's flashlight no longer works. --- "I am champion of Bellator. I am face of Bellator now. Who want with belt? Come on with cage. I am beat you. -Alexander Shlemenko