Not quite as low here in Wokingham, Stephen. The psychrometer recorded a min
rh of 22.4% at 1233, and the GEM logger in the screen (taking one sample per
minute) gave a min of 21.6 %. The accuracy of this latter instrument is not
high, so the agreement is fair, and the upward trend after 1240z to around
30% tallies on both instruments, so the psychrometer was not playing up.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.btinternet.com/~wokingham.weather/wwp.html
"Stephen Burt" wrote in message
oups.com...
Very low humidity all afternoon here (Stratfield Mortimer, on the
Berkshire/Hampshire border SW of Reading) - hourly means below 30%
12-16h, min just under 20% at 1352 UTC.

This is the lowest on my 13 year AWS record apart from the 19% recorded
on 18 June 2000. The dew point fell below 0C for a few minutes near the
lowest point.

The lowest readings were confirmed by two other adjacent and
independent sensors; the sensor itself (Vaisala HMP45C, in my Stevenson
screen) was calibrated only six weeks ago.