Weak toFlyingPoisonBugFireIce ×1.6

Attacker	Type	Moveset	DPS
Blacephalon	FireGhost	IncinerateMind BlownLegacy	68.6
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	58.7
Reshiram	DragonFire	Fire FangFusion FlareLegacy	57.0
Pheromosa	BugFighting	Bug BiteBug Buzz	53.4
Salamence	DragonFlying	Fire FangFly	52.6
Chandelure	GhostFire	Fire SpinOverheat	52.2
Moltres	FireFlying	Fire SpinFly	51.7
Cinderace	Fire	Fire SpinPyroball	51.5
Enamorus	FairyFlying	Fairy WindFly	51.2
Volcarona	BugFire	Fire SpinOverheat	50.9
Darmanitan	Fire	Fire FangOverheat	50.7
Yveltal	DarkFlying	GustOblivion WingLegacy	50.6

Clear boosts the Fire attacks above. Clear boosts Grookey.

Level 40, 15 attack IV, costed against Grookey's own defense and typing, one per evolution family.

Grookey's moveset, CP and shiny All counters Raid board

Questions people ask

What is Grookey weak to in Pokémon GO?

Grookey takes 1.6 times from Flying, Poison, Bug, Fire and Ice.

What's the best counter to Grookey?

Blacephalon with Incinerate and Mind Blown, worth 68.6 damage per second against Grookey's own defense. The full ranking is above.