The same way you take any temperature... by sampling and then averaging over the samples. Obviously you need to have enough well distributed samples to get a r

The same way you take any temperature... by sampling and then averaging over the samples. Obviously you need to have enough well distributed samples to get a reasonable accuracy, but this is all an old hat. Btw., I suspect you get that "I don't know what average temperature even means" from some nonsense Ivar Giaever spouted at a presentation that's on YouTube. The simple answer to that is that average temperature means the same thing as temperature, because temperature is always an average that we can only arrive at by sampling (since it represents the average kinetic energy of a volume of particles and you can't meassure each particle's energy individually). Ivar Giavever knows that, but he also knows that people will believe almost anything that comes from him because he has a Nobel Price. After all, his autobiography is titled "I'm the smartest man I know".