Heavy Rain will not damage any type of Pokémon in between turns in battle (unless an ability would cause HP loss).
A Pokémon holding the item Damp Rock will prolong the duration of Heavy Rain for three more turns than normal, the average being three to five turns.
Effects in Battle
- Powers up Water-type attacks by 1.5.
- Powers down Fire-type attacks by 1.5.
- Castform's Forecast ability changes its type to Water.
- Weather Ball changes to Water-type and doubles in power.
- Pokémon with the Swift Swim ability will double their speed.
- Pokémon with the abilities Dry Skin and Rain Dish will recover HP every turn.
- Pokémon with the Hydration ability will recover from status effects at the end of the turn.
- Thunder always hits and can break Protect.
- Solar Beam requires an extra turn to charge, and its power is reduced to half.
- Synthesis, Morning Sun and Moonlight will recover 1/4 of total HP, instead of 1/2.
- The Damp Rock increases the duration of the rain.
|Drizzle||This ability will summon Heavy Rain which will last the entirety of the battle, unless another weather condition is introduced to the battlefield or its effect is nullified by Cloud Nine or the Air Lock abilities.|
|Dry Skin||A Pokémon with this ability will recover 12.5% of its maximum HP at the end of every turn. It will also restore 25% of its maximum HP if attacked with Water-type moves.|
|Hydration||This ability will remove any status condition when in battle as long as it is raining. This includes removal of Sleep after use of Rest.|
|Rain Dish||6.25% (1/16) of this Pokémon's maximum HP is restored at the end of every turn when it is raining.|
|Swift Swim||The Speed stat of Pokémon with this ability is doubled.|
|Rain Dance||This move will summon (or prolong) Heavy Rain for 5 turns.|
|Morning Sun||25% (1/4) of the user's HP is restored, when Morning Sun used.|
|Moonlight||25% (1/4) of the user's HP is restored, when Moonlight used.|
|Synthesis||25% (1/4) of the user's HP is restored, when Synthesis used.|
|Solar Beam||Solar Beam's base power drops 50% (from 120 to 60).|
|Thunder||Thunder's accuracy is boosted to 100% (for a gain of 30% it's initial accuracy of 70%) . It has the potential to break through Detect and Protect at a rate of about 1 in 3 (30% of the time). This is the same for the move Hurricane.|
|Weather Ball||Weather Ball becomes Water-type. Its base power doubles from 50 to 100. Castform will receive STAB from Weather Ball in Heavy Rain.|