The Rain Badge is a Pokémon Gym Badge awarded to trainers who defeat the Gym Leader of the Mossdeep City Gym in the Hoenn region. This badge signifies a trainer's ability to handle Water-type Pokémon effectively. When a trainer earns the Rain Badge, they gain the ability to use the move Surf outside of battle, allowing them to navigate water routes. Additionally, it increases the level of Pokémon that will obey their commands, up to level 70, enhancing their overall training experience.