I was reading the "Fridge Brilliance" section on TV Tropes today, in which you look back on a seemingly minor or annoying detail and realize in hindsight it's actually quite fitting or clever, and had a thought on Luffy.
On at least two or three occasions that I can think of in the Drum Kingdom arc, Luffy is much slower than the others to notice how cold it is. At first, this seems is just a running gag at Luffy's idiocy. Then it occurred to me: Isn't rubber an insulator?
I'll be honest, I don't know if that actually is how it works in this case, which is why I'm posting here. Is it possible that Luffy's rubber body actually gives him a slightly higher tolerance for cold compared to a normal person? He's hardly immune of course, Aokiji aside he nearly froze to death climbing Drum's mountains, but his slow detection of cold weather, when he had no apparent problems quickly noticing Alabasta's heat, made me wonder.
In fact, now I think of it, wasn't there a filler episode of the Alabasta arc where the heat got to Luffy really bad/to the point of hallucination? Maybe the reverse holds true, Luffy has a lower tolerance for heat (but not as low as Chopper's) because of his rubber body.