A sensor detects the temperature outside of the car.

If the car has been stationary, the gauge may display a temperature reading that is too high.

When the outside temperature is in the range –5 °C to +2 °C (23 °F to 36 °F), a snowflake symbol lights up that warns of potentially slippery conditions.
The symbol is also illuminated briefly in the head-up display*, if the car is equipped with one.
Change the unit for the temperature gauge, etc. via system settings in the centre display's top view.