Weak toFlyingGhostFairy ×1.6

Attacker	Type	Moveset	DPS
Enamorus	FairyFlying	Fairy WindFly	26.3
Blacephalon	FireGhost	AstonishShadow Ball	25.5
Yveltal	DarkFlying	GustOblivion WingLegacy	23.3
Toucannon	NormalFlying	PeckBeak BlastLegacy	23.1
Moltres	FireFlying	Wing AttackFly	23.0
Chandelure	GhostFire	HexShadow Ball	22.8
Gengar	GhostPoison	LickShadow BallLegacy	22.8
Staraptor	NormalFlying	GustFlyLegacy	22.6
Tapu Lele	PsychicFairy	AstonishNatures MadnessLegacy	22.0
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	21.8
Dragapult	DragonGhost	AstonishShadow Ball	21.7
Salamence	DragonFlying	Dragon TailFly	21.4

Windy boosts the Flying attacks above. Overcast and Windy boost Mega Mewtwo X.

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

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

Questions people ask

What is Mega Mewtwo X weak to in Pokémon GO?

Mega Mewtwo X takes 1.6 times from Flying, Ghost and Fairy.

What's the best counter to Mega Mewtwo X?

Enamorus with Fairy Wind and Fly, worth 26.3 damage per second against Mega Mewtwo X's own defense. The full ranking is above.