User blog comment:ChishioKunrin/Maidens - Origin of Dust and the Kingdoms?/@comment-26463535-20151216074212/@comment-4010415-20151216082648

That kinda seems like a stretch, to me.

Fire is more easily associated with summer because of the heat. Wildfires occur often in summer, due to the heat and dryness.

We still don't know if Cinder has Dust infused within her, as well as sewn into her clothes. The wounds on Amber's face look like they're intended to be burn scars/wounds, so we know that Cinder was already using fire/lava beforehand.