Scandinavia is hospitable to human habitation purely because of the Gulf Stream. British Isles and Northern Europe also enjoy much milder climates due to it.

Southern Europe gets its warmth mostly from Africa. Most of the Eastern Europe is far enough from the oceans to enjoy continental climate, which means very warm summers and cold winters.

Yeah, similar to why seattle isn't nearly as cold as Chicago

In prehistoric periods they were freezing to death, homosapiens stalled out and died in Bulgaria in our first attempt to colonize Europe. The only reason that much of Europe is hospitable is because of the Gulf Stream, which I shall note is either at risk for or actively collapsing. I may be from SoCal but that sounds like a rather nice temperature personally, if my balls are outside of my body then it's too warm, y'all have to be at the edge of frostbite for me to be comfortable.