Yes, you can wear the sensor to the sauna. The temperature range of operation listed by the manufacturer is between 10 °C to 45 °C. People who have worn a sensor while in the sauna have reported that it worked just fine. Keep in mind that it may not record readings since the sensor can switch itself off at high temperatures. But it will switch itself back on when returning to a normal temperature. As a result, you may see a false spike during a sauna session.

It’s easier for the sensor to fall off when your skin is sweaty. To avoid it falling off, it’s recommended to cover it with the patch.