Stephanie,
They look great!. If you want to make them truly blow proof you might want to try some elastic and a shirt snap kit from the fabric store. Run Elastic from the top (sewn) to the bottom pocket edge and put a snap here. That way you can slip it on and snap it. If you get a big wind the material will move, elastic will strech and then it will go back into place without being able to work itself off.
Just my $.02 worth
