The Water-type Legendary Pokémon Kyogre has officially begun appearing in Raid Battles around the world in Pokémon GO. Read on below for the official announcement from the development team at Niantic:
Kyogre, the Water-type Legendary Pokémon originally discovered in the Hoenn region, is now appearing in Raid Battles around the world! Keep an eye out for Kyogre at Gyms near you, and you may be one of the first to catch this Legendary Pokémon. But don’t delay—Kyogre will only be available until 1:00 P.M. PST on February 14, 2018. Good luck, Trainers!
—The Pokémon GO team
Source: Official Pokémon GO blog