"Yeah! That's how humans do it." Probably. Look, we all know Frisk's wardrobe isn't that extensive. Now that they're hanging around with Papyrus and Mettaton, though, that's probably not going to last.

They pat the base of the snow-Frisk a few more times, then turn to start on the second part. "We should all go shopping when it starts getting colder. You guys can all get coats." Sans is the only monster they know who seems to own one and he doesn't even get cold. To be fair, most of them didn't actually live in Snowdin before.