Weak toPoisonSteel ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	58.4
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	57.4
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	55.7
Naganadel	PoisonDragon	Poison JabSludge Bomb	55.4
Lucario	FightingSteel	Bullet PunchMeteor Mash	52.9
Nihilego	RockPoison	Poison JabSludge Bomb	52.6
Roserade	GrassPoison	Poison JabSludge Bomb	51.4
Dialga	SteelDragon	Metal ClawIron Head	50.8
Munkidori	PoisonPsychic	Poison JabSludge Bomb	50.4
Regigigas	Normal	Hidden PowerCrush GripLegacy	49.8
Genesect	BugSteel	Metal ClawMagnet Bomb	49.6
Revavroom	SteelPoison	Poison JabGunk Shot	48.5

Snow boosts the Steel attacks above. Overcast boosts Cleffa.

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

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

Questions people ask

What is Cleffa weak to in Pokémon GO?

Cleffa takes 1.6 times from Poison and Steel.

What's the best counter to Cleffa?

Eternatus with Poison Jab and Sludge Bomb, worth 58.4 damage per second against Cleffa's own defense. The full ranking is above.