On 23/09/15 11:41, Graham P Davis wrote:
On Wed, 23 Sep 2015 02:30:27 -0700 (PDT)
xmetman wrote:

Yes today is the autumn equinox, and as Carol Kirkwood pointed out on
the Breakfast TV weather the start of the 'astronomical' autumn,
which to me is much more preferable to the 'meteorological' autumn.
They are both 'astronomical' in reality, it's just that in the days
before computers it was much easier for climaticians (?) to calculate
the mean value for a particular season by adding up just three
numbers rather than 90 which entailed a bit more work - well that's
my theory.

You may be right in it being the lazy solution but it's also the better
one as it matches the seasons better than the astronomical one.

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.

If the astronomical calendar is used, the middle of summer would be at
the end of the first week of August with mid-winter's day being at the
end of the first week of February. Also, December would be largely an
Autumn month and March would be a Winter one. The astronomical calendar
just doesn't tally with climatological reality.


And of course, the common name for the winter solstice does not suggest
the beginning of the season given that it is widely known as midwinter
while the summer solstice is midsummer.

All the historical celebrations of seasonal events have the equinoxes
and solstices as mid-points of the seasons. Midsummer is still a major
event worldwide. The festivals are not called that by mistake.

I have not previously heard anyone suggest those points as the
beginnings of seasons not least because they so obviously cannot be.

--
AS
pour encourager les autres