Suicune's weaknesses in Pokémon GO are, as is standard in the Pokémon series, tied to the legendary Pokémon's type. Players looking to win the battles in the currently ongoing Pokémon GO Fest Battle Challenges will need to plan to battle Suicune, as Team GO Rocket's leader, Giovanni, has the legendary Pokémon in his lineup.
Suicune Weaknesses in Pokémon GO
As a legendary Pokémon, Suicune is one of the most powerful Pokémon in the game. It is one of a handful of purely Water-Type legendary Pokémon and has a maximum CP of 2,983.
Suicune is resistant to Steel-, Water-, Ice-, and Fire-Type attacks, so players will especially want to avoid sending Pokémon of those types out to battle it. On the other hand, Grass- and Electric-Type attacks deal increased damage to Suicune, making them particularly useful.
The most effective possible counters to Suicune are other legendary Pokémon, mostly using Electric-Type attacks. Raikou and Zapdos are the two best possible options. Also viable are Magneton, Shiftry, and Salamence.