Dude.. the Water is cold no matter what in SC.
It stays between 55 and 65 depending on the season. Its just the way the current is.
If your going surfing for more than say.. 20 mins, I highly suggest a wetsuit.
Either way, I live in the Bay Area, which is closer to Surfing, yet I still ski more than surf...
I love both sports though, from the bottom of my heart.