Edgar Rice Burrough’s Barsoom (ie: Mars) is extremely Hot and Dry (and dying), so even the earth-born John Carter is dressed like that.
Dejah Thoris, Princess of the City-State of Helium is certainly no exception on such a planet. 🙂
Here’s another version of both characters by Boris Vallejo (showing that lack of armor & clothes is the norm, although John Carter is in fact a confederate soldier transported to Mars, and therefore human) :
