Following Regice, Registeel is the next Level 5 Raid Pokémon to become available! The Steel-type Regi will be available now up until August 21.

Regice has retreated from Raid Battles, but a new challenger is approaching. The next Legendary Pokémon to appear in Pokémon GO is the Iron Pokémon, Registeel. The stout Steel-type will be appearing in Gyms only until August 21, 2018, so aim to catch one before it departs. Be sure to bring your friends along with you—thanks to a recent update, you may earn some extra Premier Balls if you do.

Anyone hurrying to catch one? We have about a month to go, and then perhaps Regirock will follow!

Edited by Jake.
Thanks to Castform for the tip!

Source: Daily.pokecommunity