I think there is a big difference between white and turquoise.
I agree that geography might play a role with white bags, although there is "winter white," which is a technical term for white that is worn during the winter, although there are people who will swear it is a synonym for a barely off-white color that is not quite cream.
The bag in my avatar is the only turquoise bag I own, and I use it year-round. I live in a warm climate, but I would use it year round even if I lived on Inuit lands, maybe I am missing something but I have never heard of turquoise having any sort of seasonal or geographic implications, even by people living with fashion impalement**, even in the 1950s, even Episcopalians.
** A polite way of suggesting that an individual is plagued by the presence of a stick up their butt.