>>47495790literally the only thing that suggests it (in dp) is the snow on mount coronet and sandpoint city. alola also has a snowy mountain, do you wanna argue that alola is cold as well?
but let's still go with that logic: if the snowy mountain in the main region tells us it's cold, then the volcano and desert in the battle zone tell us it's hot, which is exactly how they're portrayed in platinum respectively.
real world climate doesn't matter, as much inspiration as they may take it's still a fictional world and in the end they can do whatever the fuck they want with it. if they wanna make russia hot, they can and will, as long as it's interesting