Density is a factor in this for sure, but I think weather/climate is also a factor. It gets cold in Boston in the winter for example, and in the PNW it's rainin

Density is a factor in this for sure, but I think weather/climate is also a factor. It gets cold in Boston in the winter for example, and in the PNW it's raining and on the cooler side for a good chunk of the year. In those climates people tend to want to get back indoors quickly and not loiter around, and that carries over even into the warmer months.