Here is a Canadian Electrical code answer. If the open deck, balcony or porch is above 2.5 meters or 8 feet then no GFCI protection is required. From a more pragmatic perspective if there is no other outlets available from grade and the porch is accessible from grade i might be inclined to ask for a GFCI regardless of the above rule. We don't require GFCI protection on balconies exposed to the elements above 8 feet and frankly we are not shocking people on their decks regardless of the weather. I am surprised at the number of GFCI protected receptacles required by the NEC and in some circumstances the lack of required protection required by the CEC. I guess Canadians don't get electrocuted as often as US citizens?
