The heat is a factor in a city's walkability, of course. Part of how that is mitigated is through flexible, mixed-use zoning laws which reduce the necessity of a car. Also, safe and accessible sidewalks, shade trees and other considerations alleviate heat exposure and make walking a healthy, viable and desirable option.

I lived in Paris and New York city. There are bodegas and grocery stores on virtually every block, so you'd look and feel foolish for getting into your car for a grocery run.

Meanwhile, whole neighborhoods in Dallas are food deserts, where you take your life in your hands just to walk to the nearest convenience store, which is likely on a "Stroad". A city doesn't have to be that way.