Sadly in Phoenix you'll find the streets entirely free of people year-round. Even when the weather is nice (Oct-Apr). I am one who walks, and often wonder if I'm just crazy when I notice I'm pretty much the only human not inside a car just walking about. I also not wonder but know it's true when I realize that hey, it really is too damn hot some days and being outside is just nuts.
For the first half of this year, I was walking about 10 miles a day through Seattle suburbs to get to/from work. During that time I think I encountered exactly two other long distance walkers, and everyone else who was outside seemed to be walking to a bus stop or taking their dog out to poop. (I've noticed that a lot of older Indian couples will get out and take a walk around the block in the afternoon, though.) I think it has something to do with cable television and Facebook.
Not just Arizona - this happen even right in the middle of downtown & midtown Atlanta, on streets surrounded by skyscrapers on either side.
I was visiting in April a few years ago and was really surprised how empty the sidewalks were despite the beautiful weather - you would see more people outside walking in a non-central residential neighborhood in berlin in the rain.
