On Wed, 23 Sep 2009 at 11:19:54, Steve J
wrote in uk.sci.weather :

The AWSs have RH electronic sensors, but they don't always agree with
each other

So I've noticed with my own instruments - and they seem to have especial
difficulty when the RH is very high.
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)