My Favorite Random Inconsequential Invader Zim Headcanon has always been that Irk is considerably farther away from it's sun and thus colder than Earth. Mostly because:
Zim didn’t know that staring directly into the sun will hurt him
and his immediate assumption is that the humans ‘booby-trapped their Sun’ - meaning he thinks this property is unique to the Earth’s Sun.
And the one time he complains about Earth’s weather, it is the intense heat that bothers him
Now, the implication in ‘Door to Door’ seems to be that it was an unusually hot day
(Jeez, Dib, if you’re sweating so much, have you considered taking off that giant black trenchcoat?? At least Zim’s a brainwashed conformist alien soldier. You’re just doing it for the Aesthetic).
But Zim still seemed a lot more negatively affected than the humans considering, like, the hallucinations.
Meanwhile, Zim has also been to the goddam North Pole and has never once made a comment about the weather there.
Plus, since Zim was originally utterly unfamiliar with the concept of rain - I figured it might make sense if his home planet was so far away from the sun that all liquids are naturally frozen solid and there’s no ‘water cycle’ even with other non-water liquids. (Although maybe it’s just that all liquids native to Irk have a really low freezing point. That’s mother alternative explanation)
