Weak toFightingGround ×1.6

Attacker	Type	Moveset	DPS
Lucario	FightingSteel	Force PalmAura SphereLegacy	27.3
Pheromosa	BugFighting	Low KickFocus Blast	25.0
Terrakion	RockFighting	Double KickSacred SwordLegacy	24.9
Blaziken	FireFighting	CounterAura Sphere	24.7
Groudon	Ground	Mud ShotPrecipice BladesLegacy	23.0
Conkeldurr	Fighting	Force PalmFocus Blast	22.8
Keldeo	WaterFighting	Low KickSacred Sword	22.6
Breloom	GrassFighting	Force PalmDynamic Punch	22.5
Urshifu	Fighting	CounterDynamic Punch	22.3
Kartana	GrassSteel	Fury CutterSacred Sword	22.1
Excadrill	GroundSteel	Mud SlapEarthquake	21.8
Marshadow	FightingGhost	CounterClose Combat	21.8

Overcast boosts the Fighting attacks above. Snow and Windy boost Dialga.

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

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

Questions people ask

What is Dialga weak to in Pokémon GO?

Dialga takes 1.6 times from Fighting and Ground.

What's the best counter to Dialga?

Lucario with Force Palm and Aura Sphere, worth 27.3 damage per second against Dialga's own defense. The full ranking is above.