Weak toFightingBugGrassElectricFairy ×1.6

Attacker	Type	Moveset	DPS
Regieleki	Electric	Lock OnThunder CageLegacy	43.4
Lucario	FightingSteel	Force PalmAura SphereLegacy	38.8
Pheromosa	BugFighting	Bug BiteFocus Blast	37.7
Kartana	GrassSteel	Fury CutterLeaf Blade	37.5
Zeraora	Electric	Volt SwitchPlasma Fists	37.2
Zekrom	DragonElectric	Charge BeamFusion BoltLegacy	36.4
Xurkitree	Electric	Thunder ShockDischarge	36.0
Terrakion	RockFighting	Double KickSacred SwordLegacy	35.4
Blaziken	FireFighting	CounterAura Sphere	35.1
Tapu Koko	ElectricFairy	Volt SwitchNatures MadnessLegacy	34.1
Breloom	GrassFighting	Force PalmGrass KnotLegacy	33.3
Enamorus	FairyFlying	Fairy WindDazzling Gleam	32.8

Rainy boosts the Electric attacks above. Fog and Rainy boost Mega Sharpedo.

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

Mega Sharpedo's moveset, stats and CP All counters Raid board

Questions people ask

What is Mega Sharpedo weak to in Pokémon GO?

Mega Sharpedo takes 1.6 times from Fighting, Bug, Grass, Electric and Fairy.

What's the best counter to Mega Sharpedo?

Regieleki with Lock On and Thunder Cage, worth 43.4 damage per second against Mega Sharpedo's own defense. The full ranking is above.