Weak toPoisonSteel ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	27.4
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	26.9
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	26.2
Naganadel	PoisonDragon	Poison JabSludge Bomb	26.0
Lucario	FightingSteel	Bullet PunchMeteor Mash	24.9
Nihilego	RockPoison	Poison JabSludge Bomb	24.7
Roserade	GrassPoison	Poison JabSludge Bomb	24.2
Dialga	SteelDragon	Metal ClawIron Head	23.9
Munkidori	PoisonPsychic	Poison JabSludge Bomb	23.7
Regigigas	Normal	Hidden PowerCrush GripLegacy	23.4
Genesect	BugSteel	Metal ClawMagnet Bomb	23.3
Revavroom	SteelPoison	Poison JabGunk Shot	22.8

Snow boosts the Steel attacks above. Overcast boosts Xerneas.

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

Xerneas's moveset, CP and shiny All counters Raid board

Questions people ask

What is Xerneas weak to in Pokémon GO?

Xerneas takes 1.6 times from Poison and Steel.

What's the best counter to Xerneas?

Eternatus with Poison Jab and Sludge Bomb, worth 27.4 damage per second against Xerneas's own defense. The full ranking is above.