Weak toGhostWaterGrassIceDark ×1.6

Attacker	Type	Moveset	DPS
Kartana	GrassSteel	Razor LeafLeaf Blade	37.9
Blacephalon	FireGhost	AstonishShadow Ball	37.6
Inteleon	Water	Water GunHydro CannonLegacy	34.1
Chien-Pao	DarkIce	SnarlBlizzard	34.1
Kyogre	Water	WaterfallOrigin PulseLegacy	34.0
Darkrai	Dark	SnarlShadow Ball	33.9
Chandelure	GhostFire	HexShadow Ball	33.6
Gengar	GhostPoison	LickShadow BallLegacy	33.6
Absol	Dark	SnarlBrutal SwingLegacy	32.9
Roserade	GrassPoison	Magical LeafLeaf Storm	32.2
Kingler	Water	BubbleCrabhammer	32.2
Greninja	WaterDark	Water ShurikenHydro CannonLegacy	32.1

Rainy boosts the Water attacks above. Clear and Fog boost Galarian Yamask.

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

Galarian Yamask's moveset, stats and CP All counters Raid board

Questions people ask

What is Galarian Yamask weak to in Pokémon GO?

Galarian Yamask takes 1.6 times from Ghost, Water, Grass, Ice and Dark.

What's the best counter to Galarian Yamask?

Kartana with Razor Leaf and Leaf Blade, worth 37.9 damage per second against Galarian Yamask's own defense. The full ranking is above.