I walk every morning, rain or shine, and all winter have been very grateful for my wool sweater, hats, scarves, mittens, legwarmers and socks. I live in Southern Arizona. Even though we didn't have snow down in the valley, it's still been cold enough to freeze a few times and cold and wet enough to see your breath many times.
I have nice cotton knit tops for the summer as well as cotton socks. Those people that work in the overly ACed buildings use sweaters, shawls and socks in the summer.
And I spend the summer knitting Christmas and birthday presents.
People in Florida don't generally need warm things either, but I bet lots of them wished they'd had them last month.....