I'm in Québec, not in Texas, so our Summer temperatures are not the same. That being said, whether I tour, commute, ride for fun or shop in the neighbourhood, I always wear normal clothing. Here are a few tips :
– Avoid light-coloured trousers.
– Clips keep trousers in check. Strictly speaking, you might only need the right one, but I like to keep both legs tucked to avoid dirtying the left leg on the bottom bracket.
– Some women ride with a skirt. I friend of mine keeps her in check with one or two clothes pins.
– Avoid too tight clothing, so you'll have some ventilation underneath. If you wear a suit, keep the tie and 1st button off until you reach destination. And keep the suit itself nicely folded in your pannier.
– If it's too warm and your ride is long, just change the top part. If you arrive at your destination, remove your riding shirt (or jersey or sweater), quickly wash your torso and put a new shirt, then you'll look fresh.
– Fenders – preferably with mudflaps – are great. You might say that you won't ride in the rain, or that you'll wear rain gear anyway, but what about those light sprinkles? Or the odd time that a short section of the road is wet, dirty, etc.? It doesn't take much to have dirty droplets thrown all over you by the wheels.
– As for shoes, I generally wear Shimano laced-up SPD shoes. They look fairly normal, work with SPD pedals and are good for long walks off the bike. When I visit shops, I bring along my safety footwear.
P.S. I haven't heard of SPD safety footwear with steel insole and steel caps.