Weak toRock ×2.56FlyingFireElectricIce ×1.6

Attacker	Type	Moveset	DPS
Glimmora	RockPoison	Rock ThrowMeteor Beam	48.9
Rampardos	Rock	Smack DownRock Slide	48.5
Tyrantrum	RockDragon	Rock ThrowMeteor Beam	45.4
Gigalith	Rock	Lock OnMeteor BeamLegacy	45.3
Rhyperior	GroundRock	Smack DownRock WreckerLegacy	43.8
Terrakion	RockFighting	Smack DownRock Slide	43.0
Blacephalon	FireGhost	IncinerateMind BlownLegacy	42.5
Tyranitar	RockDark	Smack DownStone EdgeLegacy	41.4
Regieleki	Electric	Lock OnThunder CageLegacy	40.3
Lycanroc	Rock	Rock ThrowStone Edge	39.4
Aggron	SteelRock	Smack DownMeteor Beam	38.3
Aerodactyl	RockFlying	Rock ThrowRock Slide	37.9

Partly cloudy boosts the Rock attacks above. Rainy and Windy boost Yanmega.

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

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

Questions people ask

What is Yanmega weak to in Pokémon GO?

Yanmega takes 2.56 times damage from Rock, and 1.6 times from Flying, Fire, Electric and Ice.

What's the best counter to Yanmega?

Glimmora with Rock Throw and Meteor Beam, worth 48.9 damage per second against Yanmega's own defense. The full ranking is above.