My balcony's screen door has never properly closed due to how it was installed years ago.  I created a small manget holder to attach to the door which keeps the door from opening with the wind.

For use with very strong 60 x 10 x 5 mm magnets.  This design is intended for use with screen doors.  Holds the magnet snug, but not tight enough (I recommend gorrilla glue or hot glue).

Hot glue to inside of frame, glue a magnet on the other side, within frame (if alluminum frame).  If magnetic frame, you will not need a second magnet.