Everyone makes good points. The "windows" have to let in enough light to let the hens know that it is time to wake up. They are very photo sensitive. Mine too like to squabble over who gets to sleep closest to the window. If "cold" is 32F you won't have to worry about closing them up too much. With enough hens they will create the heat they need to stay warm. My summers are nowhere near as warm as yours and it gets pretty hot and humid inside the coop if I do not have the windows open. If you want to keep it simple you can just cut holes in a couple of sides, cover them with mesh, and make a cover that you can snap on over it. If you make the holes the same size as a recycled window sash it would be pretty easy. Someone else mentioned a clear roof which would also provide light but if there is any direct sun you could end up cooking the occupants.
You want lots of:
*Light
*Chicken access
The right amount of:
*Ventilation
And no:
*Predator access
There are lots of ways to meet all of these needs.
Good luck!