Weak toGroundPsychic ×1.6

Attacker	Type	Moveset	DPS
Mewtwo	Psychic	ConfusionPsystrikeLegacy	59.7
Alakazam	Psychic	ConfusionPsychicLegacy	51.0
Groudon	Ground	Mud ShotPrecipice BladesLegacy	49.5
Azelf	Psychic	ConfusionFuturesight	49.4
Hoopa	PsychicGhost	ConfusionPsychic	49.2
Espeon	Psychic	ConfusionPsychic	49.2
Regigigas	Normal	Zen HeadbuttCrush GripLegacy	49.1
Lunala	PsychicGhost	ConfusionPsychic	48.1
Tapu Lele	PsychicFairy	ConfusionFuturesight	47.5
Latios	DragonPsychic	Zen HeadbuttPsychic	47.2
Excadrill	GroundSteel	Mud SlapEarthquake	47.0
Eternatus	PoisonDragon	Dragon TailDynamax CannonLegacy	46.6

Windy boosts the Psychic attacks above. Overcast boosts Grimer.

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

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

Questions people ask

What is Grimer weak to in Pokémon GO?

Grimer takes 1.6 times from Ground and Psychic.

What's the best counter to Grimer?

Mewtwo with Confusion and Psystrike, worth 59.7 damage per second against Grimer's own defense. The full ranking is above.