Heals status problems in rain.
Hydration is an ability that heals the user's status conditions if it is raining at the end of the turn. This includes conditions like paralysis, burn, freeze, poison, and sleep, making it a valuable ability any weather-based teams. It is only found on five Pokémon and show as a hidden ability on three of them.
Hydration will not have an effect outside of battle nor will it affect the Pokémon if it is not raining.