Samsung has released updates for the Galaxy Watch5 and Galaxy Watch5 Pro, which adds the ability to the smartwatch to measure the user’s skin temperature to track and predict menstrual cycles. The update should be available to users in the US, South Korea, and “thirty European markets”.

The new feature is the result of a partnership between Samsung and Natural Cycles, a service that uses skin temperature data to determine exactly which stage of the cycle you are in. To get an accurate estimate, you usually need to take your temperature right after you wake up. However, using the Galaxy Watch5, which tracks your metrics while you sleep, and its infrared temperature sensor, this can happen automatically.

Using this data combined with your calendar-based cycle tracking records, the Galaxy Watch5 can predict ovulation and the start of your next period. Samsung assures that the data is securely encrypted and stored only on your own device.

Based on the symptoms you record in the diary, Samsung and Natural Cycles will also offer additional advice on how to avoid unwanted effects such as pelvic pain.

To use advanced cycle tracking based on skin temperature on the Galaxy Watch5, you need to manually enter some calendar entries for your last cycle. After that, you need to enable the Predict period with skin temp option. The option will appear after updating the Samsung Health app to version 6.22 or later.