Body temperature is a measure of how hot or cold the body is, typically maintained around 98.6°F (37°C) in healthy adults. It can vary slightly based on factors like time of day, activity level, and individual differences. Body temperature is regulated by the hypothalamus, a part of the brain that acts like a thermostat. Normal body temperature can fluctuate due to illness or environmental conditions. A higher temperature may indicate a fever, often a sign of infection, while a lower temperature can suggest hypothermia. Monitoring body temperature is essential for assessing health and diagnosing medical conditions.