Buying a wetsuit for NZ conditions? Look for a 4/3mm for the colder months especially the further south you are. If you want to surf or swim in the south island through winter the better suits like Rip curl’s Flash Bomb or O’Neill’s Psycho 3 have the warmth and flexibility to get you through comfortably. 4/3mm wetsuits normally have 4mm neoprene through the chest, back and legs for warmth while keeping 3mm through the arm and shoulder panels for flexibility. Wetsuits with GBS stitching (glued and blind stitched) are warmer than flat locked stitched wetsuits due to the better seal they create, slowing the water transfer down so your body has more time to warm up. Taped stitch suits are warmer again due the almost water tight seal it creates on the seams.