Nightly Skin Temperature

The Nightly Skin Temperature measurement automatically tracks your skin temperature when you sleep. It then compares the result with your 28-day average, and shows the variation to that average. Tracking the variations in your skin temperature can help you detect changes in your body's state.

In contrast to core body temperature, which is usually quite stable around +37 degrees Celsius (98.6 °F), the temperature of your skin can vary much more. This is because the body regulates its core temperature through changing the blood flow of the skin. Also, environmental factors affect the skin temperature. A variation of +-1 degrees Celsius / +-1.8 degrees Fahrenheit is considered usual in skin temperature. Lower temperatures can occur quite often due to environmental factors, such as colder room temperature or sleeping with your hand outside the covers. Higher temperatures might be a sign of oncoming illness. Higher temperatures can also indicate being in the latter part of the menstrual cycle (ovulation and luteal phase).

The skin temperature feature can't be used as a thermometer, as it doesn't show any absolute temperature values, only the variation to your average skin temperature. If you're feeling under the weather, double-check your temperature with a thermometer.

The temperature measurement feature and data is not intended for medical purposes, diagnosis or treatment.