Weak toFlyingRockFire ×1.6

Attacker	Type	Moveset	DPS
Blacephalon	FireGhost	IncinerateMind BlownLegacy	72.8
Reshiram	DragonFire	Fire FangFusion FlareLegacy	60.4
Salamence	DragonFlying	Fire FangFly	55.7
Chandelure	GhostFire	Fire SpinOverheat	55.3
Moltres	FireFlying	Fire SpinFly	54.8
Cinderace	Fire	Fire SpinPyroball	54.5
Enamorus	FairyFlying	Fairy WindFly	54.3
Volcarona	BugFire	Fire SpinOverheat	54.0
Darmanitan	Fire	Fire FangOverheat	53.8
Yveltal	DarkFlying	GustOblivion WingLegacy	53.6
Toucannon	NormalFlying	PeckBeak BlastLegacy	53.1
Glimmora	RockPoison	Rock ThrowMeteor Beam	52.3

Clear boosts the Fire attacks above. Rainy boosts Grubbin.

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

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

Questions people ask

What is Grubbin weak to in Pokémon GO?

Grubbin takes 1.6 times from Flying, Rock and Fire.

What's the best counter to Grubbin?

Blacephalon with Incinerate and Mind Blown, worth 72.8 damage per second against Grubbin's own defense. The full ranking is above.