How long does drizzle last for?

Question

I been hearing it last for 5 turns and some say it last whole battle. Also how long would damp rock make It extend if it is 5 turns

Answer 1

Drizzle does last for 5 turns, but if you give your Pokémon a Damp Rock, it will stay rainy for 8 turns instead.
Before Generation 6, Drizzle lasted for the whole battle unless it was replaced by another weather, or an Air Lock / Cloud Nine Pokémon was sent in.

Sources: Damp Rock, Drizzle