None of the local buoys near Charleston record water temp.
So you are only tracking with satellite? It is always completely inaccurate and seems pointless to list. Our local daily surf reports take water temp from harbor (I assume NOAA base) data. SI is normally 10F higher and not near actually shore water temp.
Good news. I found a better source for the ocean temp data, that isn't showing those large biases off the Southeast coast. This is in place and are looking good to me. Please let me know if you see otherwise.