There are a few reasons that your car might be reading the wrong outside temperature. One possibility is that the sensor that reads the temperature is not working correctly. Another possibility is that there is something blocking the sensor, such as dirt or insects. If the sensor is blocked, it will not be able to accurately read the temperature. Finally, if your car's computer system is not calibrated correctly, it could also be displaying the wrong temperature. If you suspect that one of these things is causing your car to read the wrong outside temperature, you should take it to a mechanic to have it checked out.