Originally posted by zio
I took my 05 EX-L to the dealership last summer to check on the sensitivity of the outside temp gauge and I learned about the logic behind its operation. The tech tested the gauge to be normal and gave me a copy of the related page of his shop manual. Basically the temp sensor (located behind the center of the front bumper) can be affected by other abnormal heat sources and show abnormal fluctuating outside temperatures. Therefore there is a logic written into the temp indicator to prevent unrealistic air temperatures to show up (for example, a car parked in hot sun for 2 hours might show air temperature of 45 degree celsius when it is actually 25 from weather station).
If the engine coolant is 140 F. (60 C.) or higher when the ignition is turned on, it will only show the air temperature when you last turn off the key. If it is below 139 F. then the current outside air temp will be indicated. It also has some logics on how it updates the reading to prevent unwanted fluctuations - it is an interesting read. I have attached the page below for easy reference.
Now that I have a full understanding of the inner working, I feel that the gauge is pretty accurate usually within 1 degree from the radio weather report. You just have to let it update itself.
