Quote Originally Posted by Azélor View Post
If it increase the aridity there, it will also increase it somewhere else.
-12 will be too low for some places.
It wouldn't be such a bad thing if the steppes extended further north in Canada, since I think that is the case in real world Köppen maps. I think the error comes because we only use data from extreme months: the continental climates tend to have too low Tann values because of this.