a method for determining ambient air temperature outside of a vehicle with a sensor mounted on the vehicle , includes the steps of determining a road speed of the vehicle , comparing the determined road speed to a reference road speed value , if the determined road speed is below the reference road speed value , activating a device to move ambient air across the sensor , the ambient air being drawn from a location outside the vehicle , taking a temperature reading with the sensor , and , if the temperature reading is lower than a stored temperature value , storing the lower temperature reading as the ambient air temperature .