[When Ain takes his hood down, Xingqiu doesn't hide the fact that he's taking the opportunity to examine his features as if that might help give some indication of where he might hail from, but he appears to look about the same as anyone from Teyvat might.

Hopefully he lowers his gaze before Ain can notice his staring, and in the meanwhile he rubs his hands over his arms to try warming himself up. Even if it's not bothering him, he doesn't want the effects of potential frost bite (or something similar) to take hold.]

Back home, water is my element of choice. It involves being constantly wet and prone to freezing at the slightest sign of any cryo effect. I would have been frozen solid three times over normally..