Weak toBug ×2.56FightingFlyingPoisonFireIceFairy ×1.6

Attacker	Type	Moveset	DPS
Pheromosa	BugFighting	Bug BiteBug Buzz	69.7
Volcarona	BugFire	Bug BiteBug Buzz	58.8
Kartana	GrassSteel	Fury CutterX Scissor	57.5
Blacephalon	FireGhost	IncinerateMind BlownLegacy	56.0
Heracross	BugFighting	Fury CutterMegahorn	55.3
Kleavor	BugRock	Fury CutterX Scissor	54.7
Genesect	BugSteel	Fury CutterX Scissor	54.5
Vikavolt	BugElectric	Bug BiteX Scissor	54.2
Yanmega	BugFlying	Bug BiteBug Buzz	51.8
Pinsir	Bug	Fury CutterX Scissor	51.6
Frosmoth	IceBug	Bug BiteBug Buzz	51.6
Escavalier	BugSteel	Bug BiteMegahorn	51.2

Rainy boosts the Bug attacks above. Clear and Fog boost Cacturne.

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

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

Questions people ask

What is Cacturne weak to in Pokémon GO?

Cacturne takes 2.56 times damage from Bug, and 1.6 times from Fighting, Flying, Poison, Fire, Ice and Fairy.

What's the best counter to Cacturne?

Pheromosa with Bug Bite and Bug Buzz, worth 69.7 damage per second against Cacturne's own defense. The full ranking is above.