The Weather Institute is like a bureau for the Hoenn region. It checks and keeps track of weather conditions throughout Hoenn. The Weather Institute has created a Pokémon named Castform which has the ability to predict the weather and its conditions on a specific location. Its main project is the weather control machine which allows them to change the weather in areas.
On the first trip through Route 119, the player will find that Team AquaSEAS or Team MagmaROR have invaded the Institute, looking for information about Kyogre or Groudon, respectively, and the rare Pokémon, Castform. The team has also blockaded the bridge just outside the Institute, preventing access to Fortree City until the team is defeated.
This facility is used in Pokémon Emerald to find Groudon and Kyogre after defeating the Elite Four. By speaking to the meteorologist inside, players will learn of unusual weather patterns in certain routes. If he says there is a drought, Groudon slumbers in the Terra Cave; if downpours are coming down, Kyogre awaits in the Marine Cave. The other legendary Pokémon cannot be located until the first is captured or defeated.
The Weather Institute has two accessible stories, both with many desks and computers. On the far left side of the bottom floor is a PC and bed which can heal the Pokémon in one's party.
Upon entering, the first floor is accessible. By going west along the entrance hallway, there will be another opening to three rooms. The room on the western side is a rest area which contains a PC and bed which can heal the Pokémon in a Trainer's party.
The room on the eastern side is the research area where scientists work on projects and study weather patterns within the region. There are four workstations each containing a computer. There is also a computer positioned at the north side of the room, that will study and record all weather patterns within the Hoenn region. On the north-western corner of the room, there are bookshelves crammed with books and there are plants scattered around the room. The stairs to the second floor is located on the north-western corner of the room.
More workstations are located on this floor along with the head of the Weather Institute's office being up here. In total, there are ten workstations each containing a computer, one of them however is missing a chair. On the north-western corner of the room, there are bookshelves crammed with books and there are plants scattered around the room.
Right on the far western side of the room is the head of the Weather Institute's office. This is the location that Team MagmaROR/Team AquaSEAS rounded up the residents and scientists of the Weather Institute.
Once the player defeats the villainous team and saves the Weather Institute, the professor of the institute will give the player a Castform, though in Ruby, Sapphire, Omega Ruby, and Alpha Sapphire, the player must have an empty slot in the party to obtain it.
The Weather Institute contains multiple rooms with many different machines. A weather data machine stores data like temperature and weather patterns on a large computer so the employees can do tests and experiments later. There is also a huge satellite outside the institute, called the Weather Control Machine, which can control the weather. In addition, there is a study filled with books and scrap paper.
The inside of the Weather Institute made a brief appearance in a flashback in The Cavern. Team Aqua were shown to have taken over the Institute, restraining the Scientists inside and allowing Shelly to research the effects of PrimalKyogre on the weather of Hoenn.
In the manga
In the Pokémon Adventures manga
Ruby, along with a male Swimmer, ended up behind the Weather Institute while escaping from a wild Zangoose and Seviper. It was there that Norman had tracked Ruby down and battled him.