Weak toFighting ×2.56GroundBugSteelWaterGrassFairy ×1.6

Attacker	Type	Moveset	DPS
Lucario	FightingSteel	Force PalmAura SphereLegacy	33.9
Pheromosa	BugFighting	Low KickFocus Blast	31.1
Terrakion	RockFighting	Double KickSacred SwordLegacy	30.9
Blaziken	FireFighting	CounterAura Sphere	30.7
Kartana	GrassSteel	Fury CutterSacred Sword	29.3
Conkeldurr	Fighting	Force PalmFocus Blast	28.3
Keldeo	WaterFighting	Low KickSacred Sword	28.0
Breloom	GrassFighting	Force PalmDynamic Punch	27.9
Urshifu	Fighting	CounterDynamic Punch	27.7
Marshadow	FightingGhost	CounterClose Combat	27.1
Mewtwo	Psychic	CounterFocus BlastLegacy	27.0
Machamp	Fighting	CounterDynamic Punch	25.6

Overcast boosts the Fighting attacks above. Fog and Partly cloudy boost Mega Tyranitar.

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

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

Questions people ask

What is Mega Tyranitar weak to in Pokémon GO?

Mega Tyranitar takes 2.56 times damage from Fighting, and 1.6 times from Ground, Bug, Steel, Water, Grass and Fairy.

What's the best counter to Mega Tyranitar?

Lucario with Force Palm and Aura Sphere, worth 33.9 damage per second against Mega Tyranitar's own defense. The full ranking is above.