You should consider wearing a wetsuit when paddle boarding in any water temperature below 77 F (25 C). A wetsuit is an absolute must-have if you're going to paddle in any water below 65 F (18.3 C). Remember the old saying: "Dress for the water, not the weather." The day may be perfectly warm and sunny but the water can be dangerously cold (especially in early spring). The water is the real danger!