MIKE MOSS SAYS: Nick, I have to start this answer with the caveat that I am responding off the top of my head without an authoratative reference other than my own fading memory from that year! As I recall though, there was a lengthy stretch in which the RDU temperature would routinely end up about 2-3 degrees above the average of surrounding stations and that the thermometer calibration was checked by a technician a couple of times, only to find that the instrument checked out. Eventually, if I recall correctly, someone discovered that a grounds crew at the airport had cleared the area around the weather station with broad-spectrum herbicide, so that instead of a grassy or vegetated surface, there was bare ground or rocks instead, which is prone to higher temperatures in direct sunlight. It was a somewhat less extreme example of the problem one would have if the "official" weather station was set up in the middle of a recently paved asphalt parking lot!