What is the purpose of the window to you?
If it's lighting then you could just use translucent roofing. If it's ventilation then you can simply provide more of it along the eaves. Or as your in NC you may want to think of an entire open wall. Check out some threads on open air coops. It may give you some great ideas.
If it's a combination of the two and you really want windows then 2 windows open on opposite walls to provide cross wind in summer heat would work. You'll want to cover the openings with more than chicken wire, use hard wire cloth. Build the coop roof with sufficient overhang to keep rain out. Obviously if a driving rain storm you'd close the windows.
My problem with windows is exactly the reason people think they need them. Too much heat in summer. Solar radiation through glass is incredible, open the window for it. Well, if you've excellent ventilation without windows you'd not need them. If your climate is extreme heat, such as yours and to greater extent AZ, TX area, then open air coops are good ideas.
Just some thoughts.