Generation Iii
Drought
Summons sunlight in battle.
Detailed Effect
The weather changes to strong sunlight when this Pokémon enters battle and does not end unless cancelled by another weather condition. If multiple Pokémon with this ability, Drizzle, Sand Stream, or Snow Warning are sent out at the same time, the abilities will activate in order of Speed, respecting Trick Room. Each ability's weather will cancel the previous weather, and only the weather summoned by the slowest of the Pokémon will stay.
Pokémon With Drought
5 canonical Pokémon forms can have this Ability.

Torkoal
Groudon 
Mega Charizard Y
Vulpix
Ninetales