You're a funny guy, Chris. I live in the south, so I feel your pain about walking in hot weather. When I first started walking for exercise, I was very fat - I didn't live in the south then. Instead of measuring distances, I started with 15 minutes. Walk eight minutes out - go back. I didn't worry about how fast I was going, either. I added five minutes whenever the time I was walking got easy. Six months later I was effortlessly walking 90 minutes five days a week. Hills even.
Now, I don't walk much over an hour, and in summer, I'm lucky to sashay for 45 minutes. Still and all, I think walking is one of the best ways to get back to health. Walk, baby, walk.
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine