By mid-October almost all of the migrating RT's will be gone. They are at their height of migration right now. But you might be able to see a few others, but I wouldn't count on hummers that time of year.

If you don't mind driving to the coast, you can see lots of birds and wildlife at the Aransas National Wildlife Refuge.

I live about 2 1/2 hours southeast of San Antonio, so I don't know exactly what you can find in that area, but put a search in and I'm sure you will find something.