The danger for hypothermia is greatest in which situation?

Hypothermia occurs when the body's temperature drops to dangerous levels, and immersion in cold water significantly increases this risk. Water conducts heat away from the body much faster than air does, which can lead to rapid cooling, especially if the water temperature is low. When a person is submerged in cold water, even for a short period, the likelihood of the body's core temperature dropping increases. This is particularly true in temperatures below 70°F (21°C) but can occur even in moderately cool temperatures.

In contrast, immersion in warm water does not typically pose a risk for hypothermia; high winds can lead to wind chill but are less significant than the primary factor of water temperature; and high temperatures can lead to other heat-related illnesses but do not cause hypothermia. Therefore, being in cold water is recognized as the most critical and dangerous situation for hypothermia to develop.