When your screen door or storm door freezes shut in the winter, it's caused by a combination of moisture and cold air within the door and the frame. Using too much force to open a frozen door may cause damage. There are a few simple ways to minimize the chances of the screen door freezing, especially during a blowing ice storm. Primarily, they involve sealing out moisture during cold weather.
Check the weather stripping around the storm door. Glue down any areas where the weather stripping has pulled away from the door frame. Ensure there is a tight seal between the door and frame by inspecting every inch of the weather stripping.
Spray an anti-icing product around the doorframe where the screen door touches it. Either purchase a commercial anti-icing spray from a home improvement store or make your own. Mix 3 parts vinegar to 1 part water in a spray bottle and mist the door frame before a storm.
Apply a thin layer of petroleum jelly to the door frame wherever the screen door touches. The jelly will repel moisture, preventing ice from forming between the two elements. Use silicone spray instead, if you wish.