Only 110 heat index so better to be planning than doing. The fall garden in Houston is basically a cool weather garden so one does not need to get started too early unless you want to plant corn or tomatoes. I have had reasonable luck with corn, but poor results for fall tomatoes. For both of these crops ripening will occur in early November when the days are getting shorter and the weather is getting cooler (hopefully). As a result, ripening will be slow. For corn it spreads the ripening over a longer period than in the spring; not a bad thing. For tomatoes, however, ripening can take forever. Both corn and tomatoes need to be planted in August which means fighting intense heat for a long time. If you must try tomatoes, the cherry/plum type are likely to be more successful than slicer varieties.
Beans are intermediate between long growing season crops like corn and the frost tolerant winter crops. The are not frost tolerate but take only about 50 days to mature. I have successfully planted fall beans as late as early October. However, September planting is preferred.
The real joy of fall and winter gardening is the wide variety of vegetables that do well in our cool, but not cold winters. They include all kinds of root vegetables, greens, various member of the cabbages and lettuce and other salad greens. The following link gives my plan for the fall garden and approximate planting dates. 2110FW Plot