Most weather ceilings are now determined by machine (a laser
ceilometer), even if it's relayed by a human. The old balloon method
that determined ceilings by how long it took for the balloon to enter
the clouds is only used these days at those sites that don't have a
working ceilometer.

JPH

vincent p. norris wrote:
Nothing, but nothing, beats a set of human eyeballs
in the location right now to report what the weather is doing.


Human eyeballs can't always be trusted, either. Returning home to a
non-towered field shortly after dark, I was told by Unicom that the
ceiling was 700 feet. But the aircraft just ahead of me reported
breaking out at minimums--200 feet. I, too, broke out at 200 feet.

The observer was at the terminal, half a mile from the end of the
runway.

vince norris