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.
Weather Manipulation's power puts an enormous strain on the user's body, causing cellular degeneration. For Nine, this effect was worsened after receiving All for One.
Nine was very proud of his Quirk's power and its capabilities. However, due to the severe cellular degeneration of this Quirk, he sought Cell Activation to negate its effects and allow him to use Weather Manipulation to its fullest extent.
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 he was fighting on.