Abstract: Described is an integrated glass fog sensor unit utilized to provide the necessary data to predict glass fog formation. The unit includes a glass surface temperature sensor, an ambient air temperature sensor, and a relative humidity sensor. The unit is mounted on a thermal barrier tray which serves to thermally isolate the ambient air temperature sensor and the relative humidity sensor from the glass surface. A protective dome having a plurality of apertures covers the tray and sensors. A flex circuit, also acting as a thermal barrier, is utilized to complete the circuit between the sensors and the fog control unit.