A temperature sensor system for a vehicle includes a temperature sensor assembly having a thermally insulating body, a temperature sensing element thermally insulated within the body, and a thermally conductive contacting element exposed externally of the body and in thermal communication with the temperature sensing element. The thermally conductive contacting element is urged into contact with an interior cabin side of a windshield of the vehicle for sensing the temperature of the vehicle windshield. A controller, responsive to the temperature sensing element and another temperature sensing element and a humidity sensing element of the vehicle, is operable to calculate an ambient dew point and to control a cabin climate control system of the vehicle responsive to the calculated ambient dew point. The other temperature sensing element is mounted in the vehicle away from the vehicle windshield.