[bryanlarsen]

I didn't just think that, I read it in a news article about a study. My memory of what I read may be faulty, though.

Besides fewer sunlight hours, Finland also has lots of clouds and very steep sun angles which significantly affects production.

[fulafel]

The cloudiness is accounted for in the visualization, otherwise you wouldn't see that much variation on the same latitudes. But yep the sun angle affects things too like I mentioned.