I am assuming that it doesn't have a thermal break to prevent the heat from conducting out around the outside edges. Therefore the condensation forming on the cold edges of the door is freezing to the weatherstripping. Am I correct?
If so, I can suggest two things. One is to try to reduce the humidity in your house to limit the amount of condensation. This may be easier said than done. Try to use exhaust fans when cooking or showering, If this is in an unheated area, (you mentioned porch) try to allow some type of ventilation.
The second thing is the use of a lubricant around the edge of the door and weatherstripping to prevent the ice from sticking to the door. What has worked very well for me is a heavy silicone lubricant like that used to shine tires. (Black Magic Trim & Tire Shine) I use this on the bottom of my garage door and on the weatherstripping on my car doors. This prevents the doors from sticking closed from ice storms. It works for me.
Hope this helps,