Weather Manipulation allowed its user to manipulate the weather in various ways. Nine had shown he was capable of creating large storm clouds that enveloped entire islands, summon lightning bolts, and even create giant tornadoes. This Quirk also allowed him to manipulate wind and granted him flight. The storms created from this Quirk were strong enough to severely damage an entire island.
Despite it's incredible power, Weather Manipulation puts an enormous strain on the user's body, causing cellular degeneration as well as immense pain that was capable of putting Nine out of commission. This weakness had proven to be near-fatal and resulted in Nine having to use his Quirk sparingly. This effect was worsened after the villain had received All For One.
Nine's lightning bolts could also be redirected by other electricity Quirks that could act as lightning rods.
Nine was very proud of his Quirk's power and its capabilities. However, due to the severe cellular degeneration of his Quirk having ravaged his body, he sought a Cell Activation Quirk to heal himself and allow him to use Weather Manipulation to its fullest extent without facing this drawback.
Nine had used his Quirk for offensive purposes, summoning lightning bolts to incapacitate his opponents. When enraged, Nine unleashed Weather Manipulation's full power, forming a gigantic tornado and creating multiple more lightning bolts that heavily damaged the island that he was fighting on.