What would cause body temperature to raise 1.5 degrees in half a hour?

A rapid increase in body temperature by 1.5 degrees Fahrenheit in half an hour can be caused by several factors, including intense physical activity, fever due to infection, or exposure to high ambient temperatures. Stress or emotional responses can also elevate body temperature temporarily. Additionally, certain medical conditions, such as hyperthyroidism or heat exhaustion, may contribute to such a rapid rise.