Why is Weavile a top tier OU mon?

Question

the tier has a lot of fairies and fighting types

Comments

Sky high speed, high Attack, STAB Knock-off is extremely painful, STAB Ice shard for priority kills.  Only thing holding it back is that it's fragile.

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Being fragile doesn't matter much because of Heavy-Duty Boots + the fact that you can 2HKO almost every chipped switchin. Also, as Kreepy Krawly mentioned in their answer, Weavile's really fast so you can easily pick off weakened foes.

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To be honest, I's say Weavile is a top 3 mon alongside and Heatran,  Landorus-Therian. I'd go as far as to say it's the best mon in the format period.

Answer 1

If you want a long answer, you can read about it here but I'll try to summarize that for you based on my own experience

First off is it's typing. Ice is an incredible typing in ou as a lot of defensive mons such as Landorus and Corviknight don't really want to do anything it. While other defensive mons like Heatran, Melmetal and Toxapex don't mind ice types, they certainly don't enjoy Weavile's other stab, dark, and it has access to knock off. Even against mons that Weavile is never gonna break thru on its own such as the last two mentioned, it can get rid of their items and leave them vulnerable to a teammate. Thanks to ice shard, Weavile also can't be that easy to revenge killed by any faster threat that isn't scarf Lele. If those faster threats get low enough, they just turn into more victims

While Weavile's typing is very potent offensively, it doesn't really offer that much of a defensive utility especially given its rather pathetic defensive stats. That doesn't mean that it can't do anything defensively though because the key part of Weavile's typing is being able to absorb future sight and a one time switch in to what is possibly the most dangerous type in the tier, ghost. Even if you can't do it the whole game, being able to stave off ghost types once or twice could be key in a battle

Another thing that worked to Weavile's advantage is the accursed boots. Thanks to it, the thing doesn't really need to fear rocks at all. This allows it to outlast its common checks like Fini and everything mentioned earlier, Toxapex if on a hazard stacking team. While boots is the safest option, it can also go with choice band as its item for more immediate power but that would require extensive hazard removal support

Above all, Weavile's speed tier of 125. This allows it to outspeed a lot of annoying mons like Tornadus, Kartana, and whoever else and when combined with ice shard, it isn't as simple as 'I'm faster. You die', as mentioned earlier. All these things combined make it not just a top tier mon, but among the top ten

Answer 2

The OU tier is littered with threatening Dragon, Flying, Ghost, and Ground types, all of which Weavile handily deals with thanks to its STAB Knock Off and Ice Shard. Weavile also hits pretty hard and is one of the fastest Pokémon in the tier, allowing it to outspeed and KO most threats such as Garchomp, Landorus-T, and many others. Essentially, it’s one of the tier’s premier glass cannons and a top tier revenge killer, hence its placement in the OU tier and its status as one of the only viable Ice-type Pokémon in the game.

If you want to read more about why Weavile is so good, read the Sword and Shield Smogon analysis for it here.