Under which condition is a person at the greatest risk of developing hypothermia?

The greatest risk of developing hypothermia occurs when a person is immersed in cold water. This is because water conducts heat away from the body much more efficiently than air does, leading to a rapid drop in body temperature. Immersion in cold water can quickly overwhelm the body’s ability to maintain its core temperature, especially if the water is significantly colder than the body temperature.

While wearing a life jacket can provide some insulation and flotation, it does not entirely prevent heat loss in cold water. Exposure to high winds can increase the risk of hypothermia when someone is out of the water, but the immediate and most severe risk comes from the immersion itself. Swimming in warm water would not contribute to hypothermia as the conditions do not promote heat loss; instead, it provides a safe environment for body temperature regulation.