> To obtain a "all season" designation a tire has to perform in 3" of snow.
> Not much imo.
1/8 inch of snow is all it takes to strand a summer tire. Ignoring the tread pattern, all-season tires are siped (sort of) which makes all the difference on ice. I wouldn't use summer tires in the summer unless I lived in a place that didn't rain for half the year.