Cloud Nine

Cloud Nine is an ability in Polished Crystal that negates the effects of weather while the Pokémon with this ability is on the field. This can be particularly useful in competitive battles where users tend to try and use weather moves to power up as much as possible.

It's only available on two chains of Pokémon in Polished Crystal: Lickitung and Lickilicky as hidden abilities, and then Psyduck and Golduck!