Seattle is further south than most of the EU, and being down about the 45° point gets far more insolation than anywhere even five degrees north. It's just basic

Seattle is further south than most of the EU, and being down about the 45° point gets far more insolation than anywhere even five degrees north. It's just basic trig. Consider that from where I'm sitting right now the border between Canada and Alaska is only like an hour's drive north for me, albeit 4500 miles west ;-)