I was asked yesterday the definition of a "Rain Day" turning to the
http://weatherfaqs.org.uk/ it says.

"Rain day
A period of 24hr, conventionally beginning at 09UTC, during which
precipitation of 0.2mm or more has been recorded".

So if 0.2mm or more of precipitatation is recorded its a rain day. My
question is what happens when it clearly does not rain in the 24hr
period yet you have collected 0.2mm of ppn, eg in the form of FOG.
Would we record this as a rain day ? is FOG rain ?

Hope you can help

Many thanks

Paul C
www.bramptonweather.co.uk

On 11 Nov, 09:36, Paul Crabtree wrote:
I was asked yesterday the definition of a "Rain Day" turning to thehttp://weatherfaqs.org.uk/*it says.

"Rain day
A period of 24hr, conventionally beginning at 09UTC, during which
precipitation of 0.2mm or more has been recorded".

So if 0.2mm or more of precipitatation is recorded its a rain day. My
question is what happens when it clearly does not rain in the 24hr
period yet you have collected 0.2mm of ppn, eg in the form of FOG.
Would we record this as a rain day ? *is FOG rain ?

Hope you can help

Many thanks

Paul Cwww.bramptonweather.co.uk

Hi, Paul,

I understand it to be 0.2mm of precipitattion, so that is a rain day
in the monthly analysis. In the old hand-written report days two small
x characters were placed above the ob to denote precipitation from
dew / fog etc., but no such luxuries these days. Perhaps a note in the
remarks?
Anyway 0.2mm fog deposits is a rain day.
In a broadly similar vein, visibility reduced by snow / smoke to below
1000 metres is classed as fog in monthly summaries as I think the
definition is visibility less than 1000 metres.

HTH
Ken
Copley