Adult orange sulphurs closely resemble the clouded sulphur (C. philodice) but are orange instead of clear yellow. The amount of orange can vary, and hybrids are common. Both sexes have a dark border; there are pale spots within the border on females. The underside is yellow-orange with a double silver spot rimmed with reddish scales. The white female form is indistinguishable in the field from white clouded sulphurs.
Larvae are green, with a pale dorsal (along the top) stripe and a white stripe edged with black along the sides.