[Edi]

Yes, it's true. At least it was in Dominions 2 and I have no reason to assume the mechanics were changed.

Cold-blooded creatures suffer encumbrance penalties in heat/cold 0 and colder, i.e. they need heat 1 at the minimum to get no penalties.

It also occurred to me that the mod command #iceprot<bonus> that sets icearmor effects could be used in reverse by applying a negative number to the bonus. So #iceprot -2 would increase armor protection in hot provinces and decrease it in cold provinces.

Edi