On Nov 16, 11:01 am, "Eric Belton" wrote:
Bernard Burton wrote..........

Another example of excessively high screen maximum
in calm sunny conditions.

Wokingham, Berkshire, UK.

Same here in Southcote in calm sunny conditions.
Also exposure of sensor comes into play. Situated in enclosed rear garden,
with other houses in vicinity.

Last two days..........

14th +10.0
15th +10.6

Cold overnight, with Min -3.1 and Grass Min -5.0.
Temperature has risen steadily and now reads +4.2 at 1100.

Eric Belton

I think the problem here is not so much the exposure of
the whole site but sunshine on the screen at a low altitude, combined
with calm conditions, of course. The problem seems to less in summer,
ironically, the reason probably being that is very rarely calm on hot
summer days owing to differential heating on a small mesoscale and
strong convection in the lower layers. I have occasionally observed
differences of nearly 4 degC in winter between screen reading and a
psychrometer whirled in the shade. Too bad, that's the system; all
you can do is keep the screen as white and clean as possible.

Tudor Hughes, Warlingham, Surrey, 556 ft.