Hypothermia can occur on land and in the water as well as at varying temperatures. Most hypothermia cases develop in air temperatures between 30 and 50 degrees. Most outdoor enthusiast simply can't believe such temperatures can be dangerous. They fatally underestimate the danger of being wet at such temperatures. Loss of body heat to the water is a major cause of deaths in boating accidents.
Survival time does increase as the water temperature rises.
An inner layer of cotton or synthetic weave will allow ventilation. Pay special attention to protecting feet, hands, face and head. Up to 40 percent of body heat can be lost when the head is exposed. Footgear should be insulated to protect against cold and dampness. Keep a change of clothing available in case work garments become wet.