Weak toFlyingGhostFairy ×1.6

Attacker	Type	Moveset	DPS
Enamorus	FairyFlying	Fairy WindFly	31.2
Blacephalon	FireGhost	AstonishShadow Ball	30.3
Yveltal	DarkFlying	GustOblivion WingLegacy	27.6
Toucannon	NormalFlying	PeckBeak BlastLegacy	27.4
Moltres	FireFlying	Wing AttackFly	27.2
Chandelure	GhostFire	HexShadow Ball	27.0
Gengar	GhostPoison	LickShadow BallLegacy	27.0
Staraptor	NormalFlying	GustFlyLegacy	26.8
Tapu Lele	PsychicFairy	AstonishNatures MadnessLegacy	26.1
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	25.8
Dragapult	DragonGhost	AstonishShadow Ball	25.8
Salamence	DragonFlying	Dragon TailFly	25.3

Windy boosts the Flying attacks above. Overcast and Windy boost Mega Medicham.

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

Mega Medicham's moveset, stats and CP All counters Raid board

Questions people ask

What is Mega Medicham weak to in Pokémon GO?

Mega Medicham takes 1.6 times from Flying, Ghost and Fairy.

What's the best counter to Mega Medicham?

Enamorus with Fairy Wind and Fly, worth 31.2 damage per second against Mega Medicham's own defense. The full ranking is above.