I know aircon isn't nearly as common in Europe but I didn't fully understand why until I saw a chart of "average number of sunny days per year" and Chicago gets something like twice as many as London, on par with the Mediterranean coast. I remember thinking it was cloudy a lot when I lived in Cork but I didn't understand the sheer scale of the difference. But now, yeah, things are definitely changing in a way that builders decades ago didn't anticipate.