Oura measures your body temperature variations while you sleep each night. These variations are shown in relation to your baseline average, displayed as 0.0 in the Body Temperature Deviation graph.
Oura uses the data gathered over the first few weeks of use to establish your accurate baseline temperature. After that, the baseline is kept up to date continuously. So, if you feel a bit under the weather during the first weeks of use, your body temperature baseline will adjust to your normal body temperature over time.
The Body Temperature Deviation graph is visible in the trends view of the Oura app. To access it, select Trends in the app's main menu, or tap the temperature reading in the readiness view.
The Body Temperature Deviation graph has two different views. The 30-day view focuses on short-term temperature changes. The Trend view is optimized to reveal monthly body temperature fluctuations. People who menstruate typically see lower body temperature readings during the first half of their menstrual cycle (follicular phase), followed by a rise during the second half (luteal phase).
A temperature reading clearly out of your normal range will have a negative impact on your readiness score, as it typically indicates an increased need for recovery, and is a sign that something in your body status requires attention.
Read more in the Oura blog: What Can You Learn From Your Body Temperature Trends?