Heavy Rain

The Heavy Rain weather condition was introduced in the second generation of Pokemon games (GSC). It can be brought about by use of the move Rain Dance (TM18) or by the Drizzle ability

Heavy Rain will not damage any type of Pokemon in between turns in battle (unless an ability would cause HP loss).

A Pokemon holding the item Damp Rock will prolong the duration of Heavy Rain for three more turns than normal (from five turns to eight turns).