"Ken Cook" wrote in message
...
On Wednesday, 23 September 2015 23:23:14 UTC+1, David Mitchell wrote:
Generally I would say Autumn starts here in September, usually after the
first week.
Winter from the last week of November.
March is still a winter month, until maybe the last week.
Spring from end of March until the first week of June.
Having said that, the dates can be fairly flexible as I'm still waiting
for summer.

DM. Langtoft. ERofY.

David,
Summer started on 30th June and ended 1st July, followed by the customary
thunderstorm.
You must have blinked and missed it!

What's a thunderstorm? Vaguely remember them from years ago, do they involve
lightning?
By some people's definition Dartmoor has not had a summer this year with
just a handful of days over 20C.

Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
---------------------------------------------

On Thursday, September 24, 2015 at 9:56:46 AM UTC+1, Ken Cook wrote:
On Wednesday, 23 September 2015 23:23:14 UTC+1, David Mitchell wrote:
Generally I would say Autumn starts here in September, usually after the first week.
Winter from the last week of November.
March is still a winter month, until maybe the last week.
Spring from end of March until the first week of June.
Having said that, the dates can be fairly flexible as I'm still waiting for summer.

DM. Langtoft. ERofY.

David,
Summer started on 30th June and ended 1st July, followed by the customary thunderstorm.
You must have blinked and missed it!
Ken
Copley
Teesdale

I missed it Ken, but hope you enjoyed your day. :-(
No thunderstorms here for literally years. Seriously.

On Wednesday, 23 September 2015 19:38:41 UTC+1, Graham P Davis wrote:



'In the northern hemisphere, the maximum temperature occurs near the
end of the third week of July and the minimum near the third week of
January. These are only a few days from the mid-point of the
meteorological seasons.'

------------------------------------------------------------------------
I am not sure this statement is true in general for the N Hemisphere.

For example, Helsinki has on average its lowest temperatures in
February. Even more so the further north you go.

http://www.worldclimate.com/cgi-bin/...24+1102+02974W



Those dates are correct (within plus or minus 5 days) as an average of
stations in the northern hemisphere which have at least one month per
year with a mean temperature near or below 0C. How do I know that?
Because it's those stations that I used when working out those dates
fifty years ago. Unless global warming has somehow added a delay
factor, I think they should still hold true. ;-)

The reason for +/-5 days is that the dates had to coincide with the last
day of ten-day periods beginning on 1st January. This means that the
date for July should have been the 19th and not the 20th. The reason
for calculating these dates was that we needed fixed dates for the
start of the positive degree-day season after mid-winter and the same
for the negative degree-day season after mid-summer.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
http://www.scarlet-jade.com/
I wear the cheese. It does not wear me.
Posted with Claws: http://www.claws-mail.org/
---------------------------------------------------------------------------
That is the trouble with averaging over a number of locations.
The variability is lost.

'at least one month per year with a mean temperature near or below 0C.'
How near is near? Not that near surely as it would rule out a lot of stations south of 55N .

I contacted the Finnish Met Institute and the average date for the minimum temperature in Helsinki is 12th Feb.

Len
Wembury

------------------------------------------------------------------------

On Thu, 24 Sep 2015 15:50:29 -0700 (PDT)
Len Wood wrote:

On Wednesday, 23 September 2015 19:38:41 UTC+1, Graham P Davis wrote:



'In the northern hemisphere, the maximum temperature occurs near
the end of the third week of July and the minimum near the third
week of January. These are only a few days from the mid-point of
the meteorological seasons.'

------------------------------------------------------------------------
I am not sure this statement is true in general for the N
Hemisphere.

For example, Helsinki has on average its lowest temperatures in
February. Even more so the further north you go.

http://www.worldclimate.com/cgi-bin/...24+1102+02974W



Those dates are correct (within plus or minus 5 days) as an average
of stations in the northern hemisphere which have at least one
month per year with a mean temperature near or below 0C. How do I
know that? Because it's those stations that I used when working out
those dates fifty years ago. Unless global warming has somehow
added a delay factor, I think they should still hold true. ;-)

The reason for +/-5 days is that the dates had to coincide with the
last day of ten-day periods beginning on 1st January. This means
that the date for July should have been the 19th and not the 20th.
The reason for calculating these dates was that we needed fixed
dates for the start of the positive degree-day season after
mid-winter and the same for the negative degree-day season after
mid-summer.

That is the trouble with averaging over a number of locations.
The variability is lost.

'at least one month per year with a mean temperature near or below
0C.' How near is near? Not that near surely as it would rule out a
lot of stations south of 55N .


As the purpose in producing the figures was related to the production of
maps of Arctic Ice conditions, stations in areas unaffected by sea-ice
were largely irrelevant.

Yes, variability was lost and that was entirely necessary for the
purpose in hand. However, in working out the overall mean minimum and
maximum dates, I did notice something rather strange in the western
Russian Arctic. In that area, the stations showed a double minimum. I
suspect that may have been due to the short-period normals - some
only 10 years - that I had to use for several stations in the area,

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
http://www.scarlet-jade.com/
I wear the cheese. It does not wear me.
Posted with Claws: http://www.claws-mail.org/