Why a Car Thermometer Is so Bad at Reading Temperatures
Sometimes external car thermometers are so imprecise that they appear to be random number generators. In fact, they are the worst feature of a car when compared to a car’s infotainment systems . This is because they are not actually thermometers, but thermistors .
What’s the difference? Unlike a thermometer, which measures heat, a thermistor measures changes in electrical current after heat is added or removed. Thermometers and thermistors do similar things, so your machine is not so bad at measuring outside temperature (but we’re still shocked and a little upset that it’s not a thermometer).
The real reason is thermistor placement. Most thermistors are located at the front of the car behind the radiator grille (which is usually located between the two headlights).
This makes the readings less accurate, especially on hot sunny days, because they also take into account the heat radiated from the road. The measurements are most accurate when you are traveling at high speed and when the sun is not falling on the road, for example, at night or in cloudy weather.
Your automotive thermistor can still be useful when measuring freezing or freezing temperatures in cold weather, but it is important to note that this is not so accurate. You can still use it to keep track of temperature changes in different areas, but for now, we recommend installing a good weather app .