Weak toFlyingPoisonBugFireIce ×1.6

Attacker	Type	Moveset	DPS
Blacephalon	FireGhost	IncinerateMind BlownLegacy	58.2
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	49.8
Reshiram	DragonFire	Fire FangFusion FlareLegacy	48.3
Pheromosa	BugFighting	Bug BiteBug Buzz	45.3
Salamence	DragonFlying	Fire FangFly	44.6
Chandelure	GhostFire	Fire SpinOverheat	44.2
Moltres	FireFlying	Fire SpinFly	43.9
Cinderace	Fire	Fire SpinPyroball	43.6
Enamorus	FairyFlying	Fairy WindFly	43.4
Volcarona	BugFire	Fire SpinOverheat	43.2
Darmanitan	Fire	Fire FangOverheat	43.0
Yveltal	DarkFlying	GustOblivion WingLegacy	42.9

Clear boosts the Fire attacks above. Clear boosts Shroomish.

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

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

Questions people ask

What is Shroomish weak to in Pokémon GO?

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

What's the best counter to Shroomish?

Blacephalon with Incinerate and Mind Blown, worth 58.2 damage per second against Shroomish's own defense. The full ranking is above.