Weak toPoisonSteel ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	52.3
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	51.3
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	49.9
Naganadel	PoisonDragon	Poison JabSludge Bomb	49.6
Lucario	FightingSteel	Force PalmMeteor MashLegacy	48.8
Nihilego	RockPoison	Poison JabSludge Bomb	47.1
Roserade	GrassPoison	Poison JabSludge Bomb	46.0
Dialga	SteelDragon	Metal ClawIron Head	45.5
Munkidori	PoisonPsychic	Poison JabSludge Bomb	45.1
Regigigas	Normal	Hidden PowerCrush GripLegacy	44.6
Genesect	BugSteel	Metal ClawMagnet Bomb	44.4
Revavroom	SteelPoison	Poison JabGunk Shot	43.4

Overcast boosts the Poison attacks above. Overcast and Partly cloudy boost Wigglytuff.

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

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

Questions people ask

What is Wigglytuff weak to in Pokémon GO?

Wigglytuff takes 1.6 times from Poison and Steel.

What's the best counter to Wigglytuff?

Eternatus with Poison Jab and Sludge Bomb, worth 52.3 damage per second against Wigglytuff's own defense. The full ranking is above.