Earlier this year, Pokémon GO introduced the mechanic of Raid Battles, with Legendary Pokémon becoming available exclusively through Raid Battles soon after. Recently, a number of Generation III Pokémon were included in the game, and now the first Generation III Legendary Pokémon is available.
A post on the official Pokémon website confirmed that the Legendary Pokémon Groudon is now available to battle and catch from Raid Battles around the world. Looking at the image that came with the post, it looks like Groudon’s CP will be around 50,000 when battling it. It would also appear that, although abilities don’t exist in Pokémon GO, the in-game weather will be forced into sunniness while battling Groudon. The post then goes on to state that Groudon will only be available in the game until January 15, 2018, so players have one month to try to get one. There is no word so far on when Kyogre or other Gen III Legendaries will be introduced into the game, though it’s likely that their inclusions are not far off.
The Fast Attacks that Groudon may know are Mud Shot or Dragon Tail, while its Charged Attack can be Earthquake, Fire Blast or Solar Beam, so prepare for a potentially versatile moveset when getting ready to fight this Legendary.