Weak toFightingRockSteelFire ×1.6

Attacker	Type	Moveset	DPS
Blacephalon	FireGhost	IncinerateMind BlownLegacy	39.8
Lucario	FightingSteel	Force PalmAura SphereLegacy	33.7
Reshiram	DragonFire	Fire FangFusion FlareLegacy	33.0
Pheromosa	BugFighting	Low KickFocus Blast	30.9
Terrakion	RockFighting	Double KickSacred SwordLegacy	30.7
Blaziken	FireFighting	CounterAura Sphere	30.5
Chandelure	GhostFire	Fire SpinOverheat	30.2
Cinderace	Fire	Fire SpinPyroball	29.8
Volcarona	BugFire	Fire SpinOverheat	29.5
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	29.5
Darmanitan	Fire	Fire FangOverheat	29.4
Kartana	GrassSteel	Fury CutterSacred Sword	29.1

Overcast boosts the Fighting attacks above. Snow boosts Mega Glalie.

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

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

Questions people ask

What is Mega Glalie weak to in Pokémon GO?

Mega Glalie takes 1.6 times from Fighting, Rock, Steel and Fire.

What's the best counter to Mega Glalie?

Blacephalon with Incinerate and Mind Blown, worth 39.8 damage per second against Mega Glalie's own defense. The full ranking is above.