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On most cars the outside temperature display is behind the front bumper and is pretty accurate (for that location). During the summer it will read a bit higher than ambient temps because heat is reflected off the tarmac.
In the winter, it will read a tad low because that way it can fulfill its primary reason for existence - to warn you of conditions where the roadways may be freezing. Most German cars have a "bing" and a snowflake symbol when it gets to about 33/34 degrees.
If you park in the garage in the winter, then place a thermometer on the front bumper and compare it to the in-car readout the next morning.
"If you park in the garage in the winter, then place a thermometer on the front bumper and compare it to the in-car readout the next morning."
If you get two different readings the issue, of course, becomes which one is correct (or closest to). My compass reads "N" when driving north and "SSE" when traveling in the opposite direction on the same stretch of road. Hence my questioning of display accuracy.
I think this section of the owners manual explains it well. The sensor can pick up heat radiating from the road, the engine, or just from the body panels that have been sitting in the sun. To minimize the effect of these things, it is necessary to have good airflow across the sensor. In other words don't believe what your thermometer is saying unless the car is moving. If at that time the temperature reading doesn't agree with the actual temperature, a correction factor can be added within the cars settings.
Also don't trust the temperature given on a radio station. The temperature can vary several degrees over just a few kilometers. You need to use your own thermometer to check the local temperature. I use a digital indoor/outdoor thermometer, and hang the outdoor probe through the drivers window as I am driving.
temp sensor is really only accurate when the car is moving. when you come to a stop even in the winter time radiant heat will affect the reading... you can see how accurate it is by mixing up some water with ice and sticking the probe into it. it should read 32F
Yup what everyone else has said. Notice how when you turn the car on, it will say X degrees, then as you drive around after about 10 minutes, it either goes up or goes down even more? This is because it is all based on air flow. I will say mine on the 07 is VERY accurate, but I know that doesn't help you with a 2G rdx.
This morning I went out and placed my calibrated lab-grade electronic thermometer up inside the front bumper, then waited about 1/2 an hour for the reading to stabilize. I did not start the vehicle and the sun was not shining. The dash readout was 13 Celcius, the calibrated thermometer read 14 C. This difference in Fahrenheit is 1.8 degrees F.
Most decent commercial non-critical non-calibrated systems that read temp should have an accuracy of about +/- 3 degrees F. That's the best you can expect from a thermocouple or thermistor,
The vehicle probably has a thermistor type sensor since they are cheaper than a thermocouple and the ruggedness etc of a thermocouple is not required for that application. I know of what I speak.
So I'm not in the least surprised it was only off by a degree C. I recently checked the temp accuracy of a $200 reptile egg incubator I have here, it had a thermistor, it was off by less than 2 F.
01-14-2016, 01:15 PM
