The hypothalamus is a part of the brain that is responsible for producing hormones that regulate body temperature. It becomes more active at night, which can lead to an increase in body temperature when you are sleeping. In addition, due to normal metabolic functioning, it is normal to expect an increase in body temperature as the day progresses.

Body Temperature It tends to go up and down a little during the day, and the same is true at night, although while you’re sleeping it can be 1 to 2 degrees lower than in the daytime. Body temperature starts to fall as bedtime approaches, paving the way for a good night’s sleep.

Starting two hours before sleep and lasting until morning, the body’s core temperature cools and the skin temperature rises which may cause some people to feel warm at night. The body cools itself by releasing heat through vasodilation, meaning dilated blood vessels.

When you finally nod off, your body will continue decreasing its temperature — around 2°F (-1°C) in total — to help promote a good night’s sleep. And when it’s time to wake, the temperature will begin rising again to its usual level, according to Sleep.org. Sweating happens to cool your body’s core temperature when it rises above a certain point.

As core body temperature dips at night to promote sleep, skin temperature may rise, making us feel hot. External factors can also make us feel hot at night, including bedding and pajamas, pre-bed activities, hydration level, hormones, and illness.