Thundurus is hitting Pokémon Go's tier five raids starting on March 2.
Thundurus is the second of the Forces of Nature trio to join the game, following Tornadus. This means Landorus will likely join raids starting in April, though an end date for Thundurus' raids has yet to be announced.
Just like Tornadus, Thundurus has two forms: the human-like Incarnate Forme and the bird-like Therian Forme. The typing of the Pokémon doesn't change between forms, so all these counters should work no matter what. The Therian Forme has yet to make a debut in Pokémon Go.
Thundurus is only weak against rock - and ice-type Pokémon, so consider using any of the following:
Rampardoswith Smack Down and Rock Slide
Mamoswinewith Powder Snow and Avalanche
Tyranitarwith Smack Down and Stone Edge
Rhyperiorwith Smack Down and Rock Wrecker
If you're having trouble, remember to use weather boosts to turn the tides in your favor. Rain will boost electric-type moves and partly cloudy weather will boost rock-type moves.
The best moveset on Thundurus is Thunder Shock and Thunder, though it's not that great of an PvE attacker. However, it does have a high attack stat and its downfall is its limited moveset. If Niantic decides to add better electric-type moves to its pool in the future, it'll be a great attacker, so consider picking one or two up and holding on to it, just in case.
For more information on raids, check out our guide here.