"Adrian D. Shaw" wrote in message
...
Between 17:30 and 20:30 this evening we had around 40mm of rain
according to
my automatic (LaCrosse WS-3600) weather station. According to my
manual
cone-shaped gauge, which is fairly close by, we had around 18mm.
The automatic gauge is around 1 metre above ground level, and the
manual
gauge is stuck into the soil.
The automatic seems to correspond well with the manual in normal
conditions.

.... If you have had readings that have corresponded well in the past
(over a long period), then I would suspect a 'one-off' problem with one
or other of the gauges: the declared rainfall from the LaCrosse sounds
high to me - the showers etc., yesterday were pretty heavy, but I'm not
sure we had anything quite that perky.

Try doing a test with the auto by putting a measured amount of rainfall
through it. As you had a thunderstorm, would there be any lightning
interference with the system?

Even with high-end professional kit, things can go wrong (witness
Heathrow/03772 last couple of days), so don't necessarily go out and
replace the gauge / electronics etc., just yet: might have been a
one-off 'glitch'.

Martin.

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