Otterman.........
You asked:
What are the requirement for measuring an ATIS temperature? At my home base the setup is insane, with over ten temperature probes which are averaged out. At most stations in the less developed world, it is measured at only one place, somewhere on the aerodrome environment.
The answer's here:
ICAO DOC 8896 MANUAL OF AERONAUTICAL METEOROLOGICAL PRACTICE
2.3.12 Air temperature/dew point temperature
2.3.12.1 Observations of air temperature and dew point temperature should be representative of the whole runway complex.
Also, if you refer to ICAO ANNEX III as suggested by Boxshifter, you'll see in Appendix 3, Section 4. OBSERVING AND REPORTING OF METEOROLOGICAL ELEMENTS that:
4.6 Air temperature and dew-point temperature
4.6.1 Display
Recommendation.— When automated equipment is used for the measurement of air temperature and dew-point temperature, air temperature and dew-point temperature displays should be located in the meteorological station with corresponding displays in the appropriate air traffic services units. The displays in the meteorological station and in the air traffic services units should relate to the same sensors.
4.6.2 Reporting
4.6.2.1 In local routine and special reports and in METAR and SPECI, the air temperature and the dew-point temperature shall be reported in steps of whole degrees Celsius. Any observed value which does not fit the reporting scale in use shall be rounded to the nearest whole degree Celsius,
with observed values involving 0.5 [degree] rounded up to the next higher whole degree Celsius.
As JT suggests, perhaps it might be just as well to let sleeping dogs lie?
