For super cold waters, go with an O'Neill PsychoFreak 4.5/3.5MM FSW Wetsuit, its double lined, XDS-Air neoprene will keep you toasty and dry in almost any situation, and it's insanely flexible where you need it most. Throw in an external key-pocket, D-Tox knee pads, plasma seals, a drain hole, and a double Superseal neck, and you'll see why I can call the O'Neill Psycho Freak 4.5MM Wetsuit the last one you'll ever buy for cold water surfing.
