Ruin Explorer
Legend
She literally does it in the first episode of the cartoon - like, the first ever one, back in 1992. And she's done it ever since.As far as I know, Storm and Jean don't have mutant abilities to create clothing out of thin air, which is why it was jarring to me, it seems to defy the established lore of the world we are presented.
Yes in the comic books she definitely doesn't have the mutant power to do that - yet still does it at times - but in the TV cartoon, her power set has always encompassed instant costume changes. Surprising as that may be.