I was about to say that it'd beat a bottle of wine from Sweden, anyway, but felt the need to fact-check my joke, and apparently Swedish wine is a thing!
Looking at the weather averages for Duluth (chosen at random), no, that actually looks probably colder than the heavily populated bits of Sweden, certainly in the winter.
The wine region is the little corner of Michigan just north of Indiana. They also do apples and cheese. I’m not sure how far north the region extends, but I’ve been there a few times. So that’s quite a bit farther south than the Swedish peninsula.
So, _London_ is further north than anywhere in the contiguous United States. But obviously much warmer than a lot of it, particularly in winter (London rarely gets far below 0 Celsius). Latitude very much isn’t everything.
If you look at the prevailing winds off of the eastern atlantic, it looks a lot like Southern Sweden gets the same air that London does. Plus there's a couple of considerable lakes along that path, so grapes do seem plausible.
