>>14424126I hope my climate theory is right, I'll be so proud if I have solved this mystery. (I suggested it first last night).
The basic idea is that your real-world country (or the one the 3DS is assigned to) will influence the Vivillion's colour scheme based on said country's real-world climate.
Canada is in a subarctic region and got Polar, Norway got Tundra and it has a Tundra climate, France/Spain have Marine climates, Poland has a Continental climate and Mexico has an arid/semi-arid climate that equates to the Sun forme.
I'm unsure about some of them though. Modern for the US doesn't fit any climate pattern. I can make cases for Garden and Meadow, but it's a stretch.
There's something else missing from the puzzle...