Actually, in reference the Antartica being used, and the 'hunting only in the hottest parts of the world during the hottest time of the year' ... the Predators that were there, weren't "Blooded" in otherwords, it was a right of passage, and it wasn't going to be easy on them.
Also, they wore heated netting, to keep their body temperature at a constant level.
Granted, they did it stupidly, and it -should- have been in the future on a colonist planet, but there actually is basis going back to the books.
.... Excepting the fact that Predators are supposed to be forbidden from hunting humans, because the challange isn't there in most cases .... but the Predator movies blew that out first anyway.