The Pokémon summons a hailstorm when it enters a battle.
Snow Warning is an ability introduced in Generation IV. So far, 4 Pokémon have this ability.
Snow Warning creates a hailstorm when the bearer enters battle. The effect lasts 5 turns (8 if the user is holding an Icy Rock,) unless it is cleared via Cloud Nine or replaced by another weather condition.
Outside of battle
Snow Warning has no effect outside of battle.
Pokémon with Snow Warning