Weather Institute is a facility dedicated to studying the weather on Route 119 in the Hoenn. It is used to tracked the weather throughout the region. During the events of Ruby and Sapphire and their remakes, the facility is attacked by the enemy team to steal data on legendary Pokémon.
Prior to the events of the games, the team of scientists at the Weather Institute create Castform to help predict the weather. When the player arrives at the institute, Team Aqua (Sapphire and Emerald) or Team Magma (Ruby) has taken over the facility looking for data on their desired legendary Pokémon. The team has also blocked the bridge, preventing the player from going forward on the Route until the team is defeated. After defeating the Team Aqua or Magma admin, the scientists are rescued and the professor of the institute will give the player a Castform.