I think heredity has *lots* to do with it. Skunk streaks are part of the dominate/ resessive gene "thing".
I do not discount the additional factor of oxygenation; gray hair can be linked to it. Anti oxidents in diet and vitamins can retard the oxygenation process of the body. It is true that a sudden shock can cause grayness. I've seen it happen!
I do not know anything about my "season", but my gray hairs have a ton of natural shine and a refreshing brightness.
I love to see the freshness of a blue black salt and pepper head of hair. Sigh, my hair will never be that, but I love what I have.
This forum is about our personal choice to be NC and CG's. Gray (grey?) is also a matter of choice; I chose not to color and I chose to be gray.