Brazilians are probably on the other end of the extroversion spectrum. But I should repeat that I don't think Finns are no longer significantly different from other Northern Europeans. And as I explained, the cold weather has never directly caused anything. We are less taciturn now than we used to be in the past despite the climate being essentially the same.

Warm weather does not make a population extroverted by itself. Southern Japan is as hot and humid as Brazil for most of the year but the Japanese are not known as samba loving extroverted chatterboxes.