Weak toFightingBugFairy ×1.6

Attacker	Type	Moveset	DPS
Lucario	FightingSteel	Force PalmAura SphereLegacy	24.2
Pheromosa	BugFighting	Bug BiteFocus Blast	23.5
Kartana	GrassSteel	Fury CutterSacred Sword	23.0
Terrakion	RockFighting	Double KickSacred SwordLegacy	22.1
Blaziken	FireFighting	CounterAura Sphere	21.9
Enamorus	FairyFlying	Fairy WindDazzling Gleam	20.4
Conkeldurr	Fighting	Force PalmFocus Blast	20.2
Keldeo	WaterFighting	Low KickSacred Sword	20.0
Breloom	GrassFighting	Force PalmDynamic Punch	19.9
Urshifu	Fighting	CounterDynamic Punch	19.8
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	19.6
Marshadow	FightingGhost	CounterClose Combat	19.3

Overcast boosts the Fighting attacks above. Fog boosts Umbreon.

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

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

Questions people ask

What is Umbreon weak to in Pokémon GO?

Umbreon takes 1.6 times from Fighting, Bug and Fairy.

What's the best counter to Umbreon?

Lucario with Force Palm and Aura Sphere, worth 24.2 damage per second against Umbreon's own defense. The full ranking is above.