It does if you burn the sky. Everything I've heard from the ghouls and read in prewar books makes it sound like the weather used to be a lot different. It actually rained and there used to be plants outside Oasis, which is a mutation thing, and Lookout Point, which is an island. Well, I guess we have some plants. Poisonous succulents, mostly.

Anyway, the only ice I've seen in real life was inside a freezer I found once that still had undecayed coolant.