The cover star of Pokemon Ruby game, the Legendary Pokemon Groudon is now available in Pokemon Go in the Raid battles. It is first Legendary Pokemon from the third gen of games to be obtainable in the Pokemon Go.
last week game received 50 Ruby and Sapphire Pokemon and new dynamic weather system, now Groudon is in the game. Groudon is the ground-type legendary Pokemon available in the Hoenn region.
You have a limited time to catch the Groudon because will only be available until 1: PM PST on January 15, 2018. You can also see the official source here.