Generations III to V
Drizzle summons rain in battle as soon as a Pokémon with Drizzle enters the battle. Its effects are the same as the move Rain Dance, but instead of lasting for a limited amount of turns, it lasts for the whole battle (unless it is replaced by another type of weather). If a Pokémon with Drizzle is sent out in the same turn as another Pokémon whose Ability affects the weather, the slower Pokémon's Ability will override the faster Pokémon's Ability.
Generation VI onward
The rain now lasts only for five turns. This can be extended to eight turns if the Pokémon is holding a Damp Rock.
Rain called by Drizzle does not allow Sliggoo to evolve into Goodra.
Drizzle will not activate if the Pokémon it's on is a Kyogre that's in position to undergo Primal Reversion; in that case the Primal Reversion will happen instead, its ability will be replaced by Primordial Sea, and only that ability will activate. Drizzle will also fail to activate if heavy rain, extremely harsh sunlight, or strong winds are already in effect.
Outside of battle
Drizzle has no effect outside of battle.
In Red Rescue Team and Blue Rescue Team, and Explorers of Time, Darkness and Sky, Drizzle changes the weather to Rain upon entering a floor, and then every subsequent 36 turns.
In Super Mystery Dungeon, Drizzle changes the weather to rain upon entering a floor. Rain lasts a certain number of turns (in multiples of 66) before clearing. After the weather has cleared, Drizzle will again activate after waiting a certain number of turns (in multiples of 66).
||Changes the weather to rainy.
||Changes the weather to a rain condition.
||てんきを あめに してしまう
||The weather on the floor will be rain!
||The weather condition on the floor will be Rain.