Hypothermia is characterized by a lower than normal:

Hypothermia occurs when the body’s core temperature drops below the normal range, typically considered to be around 98.6°F (37°C). In cases of hypothermia, as the body loses heat faster than it can produce it, especially in cold water or environments, the core temperature decreases, leading to physiological responses that can be harmful or even life-threatening.

While body extremity temperature, total body temperature, and body skin temperature may be affected in a hypothermic situation, the primary and most critical measure of hypothermia is the core temperature. Core temperature is vital because it reflects the functioning of the body’s internal processes, including metabolism and organ systems, which can become severely impaired if the temperature falls too low.

Therefore, recognizing a drop in core temperature is crucial for diagnosing and managing hypothermia, making it the defining feature of this condition.