Weak toFlyingWaterGrassPsychicIceFairy ×1.6

Attacker	Type	Moveset	DPS
Mewtwo	Psychic	ConfusionPsystrikeLegacy	28.0
Enamorus	FairyFlying	Fairy WindFly	27.0
Kartana	GrassSteel	Razor LeafLeaf Blade	26.4
Tapu Lele	PsychicFairy	ConfusionNatures MadnessLegacy	25.2
Yveltal	DarkFlying	GustOblivion WingLegacy	23.9
Alakazam	Psychic	ConfusionPsychicLegacy	23.9
Inteleon	Water	Water GunHydro CannonLegacy	23.7
Toucannon	NormalFlying	PeckBeak BlastLegacy	23.7
Kyogre	Water	WaterfallOrigin PulseLegacy	23.6
Moltres	FireFlying	Wing AttackFly	23.6
Staraptor	NormalFlying	GustFlyLegacy	23.2
Azelf	Psychic	ConfusionFuturesight	23.2

Windy boosts the Psychic attacks above. Clear and Overcast boost Great Tusk.

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

Great Tusk's moveset, CP and shiny All counters Raid board

Questions people ask

What is Great Tusk weak to in Pokémon GO?

Great Tusk takes 1.6 times from Flying, Water, Grass, Psychic, Ice and Fairy.

What's the best counter to Great Tusk?

Mewtwo with Confusion and Psystrike, worth 28.0 damage per second against Great Tusk's own defense. The full ranking is above.