Roy Smith wrote:

So, what's the definition of "reported"?

Reported by a certified machine like ASOS or a certified weather
observer that has been placed there by official sources.


Why does the accredited observer
on the ground telling me on the radio "measured visibility is 2 miles" not
count as a report?

He has no way of officially knowing that without all the infrastructure
in place, such as visibility charts.



I have received ATC communication via pilot relays when out of radio
contact, and served as a relay for other aircraft when they had the same
problem. Why is it OK for me to relay "ATC wants you to switch to 129.05",
but not "my observer reports 2 mile visibility"?

Because that's the way the rules are currently written.