it does help that you have quite tall mountains
not necessarily because temperature inversion tends to play a big role especially in polar latitudes : http://slideplayer.com/slide/5233026/
For example, the mountains of Eastern Siberia are warmer than the plain below them.

I asked where the equator was because on Earth, temperatures are largely dependent on the latitude and the angle of the Sun. So if the red line is the hottest, it is likely the equator unless your planet has different characteristics. And generally, desert are rare around the equator, except in Eastern Africa. It has something to do with the direction of the winds that tend to hug the coast instead of going inland.

If I follow the yellow line, Glacier pound should be warmer and Skadi colder. Skadi needs to be colder also because it sits at the eastern edge of the continent and the dominant winds comes from the arctic region in the west. (most of the time)
Steppes are unlikely at this latitude. It is cold, so in order to have enough evaporation, it need to be really dry. Apparently, some areas in Northern Alaska are dry enough to be considered steppes but not all maps agree with this.
Glacier pound world be like Norway or even warmer depending if the yellow line is roughly the equivalent of the arctic circle.

most people though the world was on a plate surrounded by water
yes but most people were also illiterate and never travelled more than a few miles away from home.