You should really take a look at the birthright setting cause your climate is mostly following Cerilia's one. Just do a quick research on the net for birthright stuff

Rjurik: a north of Canada like setting with serve winter.

Brechtur: a temperate coastal country cause by the warm water, the mountains keeps the temperature in the country and the cold out.

Vosgaard: a Norse like ice setting

Khinasi : desert setting (mostly where Cerilia is written on the map) that goes up to moderate temperature in the north and the east.

Anuire: a temperate weather like in England

As for Aduria and Thaele, I’m not sure, but I would go with your temperature.

Quote:
“(I'm not really sure how to explain severe cold on one shore but not on the other, or a moderate spot on an Island which is warm), especially when I did that thinking of temperature @Ground Level.”

For your frost problem, you could use one of the following reason: glacier in the north stream; an ice meteor that crash around there; or a magical explanation like the white witch that live in the Rjurik forest or another reason of your choosing.

For the southeast island just make all your water currents converge around that island.

Hope I help u a bit,
Alu.

P.S.: how do I do a normal quote ?