And for the 2015 IRC folks.....
E4002.8 Damp locations. A receptacle installed outdoors in
a location protected from the weather or in other damp locations
shall have an enclosure for the receptacle that is weatherproof
when the receptacle cover(s) is closed and an
attachment plug cap is not inserted. An installation suitable
for wet locations shall also be considered suitable for damp
locations. A receptacle shall be considered to be in a location
protected from the weather where located under roofed open
porches, canopies and similar structures and not subject to
rain or water runoff. Fifteen- and 20-ampere, 125- and 250-
volt nonlocking receptacles installed in damp locations shall
be listed a weather-resistant type. [406.9(A)]
E4002.9 Fifteen- and 20-ampere receptacles in wet locations.
Where installed in a wet location, 15- and 20-ampere,
125- and 250-volt receptacles shall have an enclosure that is
weatherproof whether or not the attachment plug cap is
inserted. An outlet box hood installed for this purpose shall be
listed and identified as “extra-duty.” Fifteen- and 20-ampere,
125- and 250-volt nonlocking receptacles installed in wet
locations shall be a listed weather-resistant type. [406.9(B)(1)]