There are only a few shuttle missions left so catch this sight while you can and while the weather permits. When the shuttle is docked on the ISS, the pair is a very bright object in the evening sky. Now this is just around dusk, but it should still be quite visible. Fortunately, there shouldn't be too many clouds either on this breezy and warm evening.
Look in the northwest sky around 8:36 pm. You should see a steady bright light moving high in the sky. If the lights flash or if you hear a sound like an engine, that's not the ISS and shuttle. The joined spacecraft are silent and will be visible for about 3 minutes. The bright object will move from northwest to southeast. Enjoy the show, it may be our last chance, depending on the path of future missions and the ever-fickle Houston weather.
Remember, you can find out when to look for future fly-overs of the remaining shuttle missions as well as the ISS by going to spaceweather.com/flybys/. You just enter your zip code.