Would wearing 2 full summer wetsuits be the equivalent to wearing one winter suit?

Heu... base on this as a standard. Heat is lost more quickly in water than on land. Water temperatures that would be quite reasonable as outdoor air temperatures can lead to hypothermia. A water temperature of 10 �C (50 �F) often leads to death in one hour, and water temperatures hovering at freezing can lead to death in as little as 15 minutes. Water at a temperature of 26 �C (79 �F) will, after prolonged exposure, lead to hypothermia.