At What Water Temp Do You Need a Wetsuit?

It depends on the water temperature, air temperature, wind, and your aversion to cold. For a more in depth look into these factors and for the whole water temperature / neoprene thickness chart go here. But a quick answer to this question with assumption that none of the factors go into extremes (air, wind, and how quickly you feel cold) – you need to put something on for protection if water temperature drops under 77F (25C). Probably a neoprene top is enough in the beginning, then shorty, springy etc…and so on as the temperature drops.