The American interior generally does not benefit from the same moderating influence of major water bodies as Scandinavia does. The winters are quite different. That's why you can have frequent awfully cold conditions as far south as Oklahoma (and sometimes Texas) despite being as far south as Egypt or Jordan.
As others pointed out, I nitpicked the one place in Scandinavia that would actually get cold, to make the comparison fair. Places further north than Rovaniemi (my example) that are closer to the ocean, like Tromsø, have milder winters due to the moderating influence of the Gulf Stream.
This is a fairly well-known concept. From a starting place in Europe, usually one has to travel 10-15 degrees of latitude south to find similar winter temperatures in North America. See:
- Helsinki, Finland vs. Syracuse, NY: 17 degrees of latitude
- Warsaw, Poland vs. Pittsburgh, PA: 12 degrees
- Berlin, Germany vs. Roanoke, VA: 13 degrees
You have to go into Russia to find truly cold winters. Kazan, probably the coldest major city in the European side of Russia, has similar winter temperatures to Edmonton, AB, only two degrees further south.
Neither does most of America. You nitpicked one place in NA then forgot sweden finland and norway exists...