Originally Posted by
AerocatS2A
Your car doesn't know what the temperature is. Your car knows what the temperature at the sensor is, but that's not the same thing at all, especially if it's been sitting in the sun on the same piece of tarmac for a while.
Fair point and perhaps I was being facile, but absolutely soluble at machine level. If it was important to my car then it would probably take the data from some 'nearest weather station'. METAR are already expressed in a form interpretable by a very simple machine. I am expressing lack of understanding as to why this ability is not used in performance calcs, as a check on human performance if nothing else.