It can affect people's plans to paint their miniatures. Not everyone has airbrushes and people depend on weather conditions to prime or varnish.
I'm curious how far north you have to be for autumn to be that bad. At least in the notoriously-always-raining-UK (more true in the last couple of years that it's been for a while), it's not been that difficult to find a day to spray/varnish even in winter (at least in the midlands), so it's never been a concern I've had to think about seriously. (Hell, for my Dad (previous to retirement, anyway) wargaming always had emphasis more when he couldn't go out for a bike ride and whatnot in autumn/winter.) Sure, winter I can see if you are in a place where you get regular snow (we don't anymore), so like, Canada and Alaska and such I suppose must have the issue and by extension some of the north US. Scotland maybe? I genuniely am curious.