What does rain dance do in Pokemon?

The Rain Dance move in Pokémon causes rain to fall for five turns, changing the weather on the battlefield. This weather condition benefits Pokémon with the Swift Swim (doubles Speed in rain) or Hydration (heals status in rain) Abilities, and powers up Water-type attacks while hindering Fire-type attacks. Certain moves also become more accurate, or can have added effects or damage in weather.