Weak toFighting ×1.6

Attacker	Type	Moveset	DPS
Lucario	FightingSteel	Force PalmAura SphereLegacy	27.4
Pheromosa	BugFighting	Low KickFocus Blast	25.1
Terrakion	RockFighting	Double KickSacred SwordLegacy	25.0
Blaziken	FireFighting	CounterAura Sphere	24.8
Kartana	GrassSteel	Fury CutterSacred Sword	23.7
Conkeldurr	Fighting	Force PalmFocus Blast	22.9
Keldeo	WaterFighting	Low KickSacred Sword	22.6
Breloom	GrassFighting	Force PalmDynamic Punch	22.6
Urshifu	Fighting	CounterDynamic Punch	22.4
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	22.3
Marshadow	FightingGhost	CounterClose Combat	21.9
Mewtwo	Psychic	CounterFocus BlastLegacy	21.8

Overcast boosts the Fighting attacks above. Partly cloudy boosts Regigigas.

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

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

Questions people ask

What is Regigigas weak to in Pokémon GO?

Regigigas takes 1.6 times from Fighting.

What's the best counter to Regigigas?

Lucario with Force Palm and Aura Sphere, worth 27.4 damage per second against Regigigas's own defense. The full ranking is above.