I have a controversial, non-scientific view: When you live in a place with better weather, your mental health is better. This has enormous second order effects. (I have no idea if this can be scientifically explained due to UVA/UVB exposure.) I grew up in place with horrible, long winters. When I finally escaped to places with better weather, it was life altering. I will never forget living as a university student in Silicon Valley. My otherwise unimpressive apartment had an orange tree in the backyard. I could pick the oranges and eat them. Weeks elapsed where there wasn't a single cloud in the sky. I cannot stress enough how much this improved my mental health.