My average temperature graph for January (1990-2010) shows low temperatures
at the beginning and end of the month and relatively high temperatures at
mid-month. This appears to be due to the fact that every year in January we
seem to get a few days of more or less strong SWlies which of course raises
the temperature appreciably. This has occurred at various times of the
month, so the average puts it in the middle, I suppose. For example I have
as 21-year means:
Jan 1st 2.1C
Jan 15th 4.4C
Jan 31st 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

On Friday 07 Jan 2011 17:34, Ian Bingham scribbled:

My average temperature graph for January (1990-2010) shows low
temperatures at the beginning and end of the month and relatively high
temperatures at
mid-month. This appears to be due to the fact that every year in January
we seem to get a few days of more or less strong SWlies which of course
raises
the temperature appreciably. This has occurred at various times of the
month, so the average puts it in the middle, I suppose. For example I
have as 21-year means:
Jan 1st 2.1C
Jan 15th 4.4C
Jan 31st 2.3C


On a slightly larger scale, forty-odd years ago I extracted temperature data
for Arctic stations from the WMO 31-60 normals. Most stations only had the
51-60 period so that's a problem but many showed January to be warmer than
December or February. I think the bulk, if not all, of the stations showing
this feature were in the Soviet Arctic.

--
Graham Davis, Bracknell
It was raining cats and dogs and I fell in a poodle. [Chic
Murray(1919-1985)]

On Jan 7, 5:34*pm, "Ian Bingham"
wrote:
My average temperature graph for January (1990-2010) shows low temperatures
at the beginning and end of the month and relatively high temperatures at
mid-month. *This appears to be due to the fact that every year in January we
seem to get a few days of more or less strong SWlies which of course raises
the temperature appreciably. *This has occurred at various times of the
month, so the average puts it in the middle, I suppose. *For example I have
as 21-year means:
Jan 1st * 2.1C
Jan 15th *4.4C
Jan 31st * 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

A very similar pattern here over the 20 years of my records. In fact
the 15th is the mildest day of the month with a mean temperature of
8.2C.

There are marked colder spells each side, the low points being:-

8th 6.7C
26th 6.2C - The coldest day of the winter over 20 years.

Graham
Penzance

Graham Easterling wrote:
On Jan 7, 5:34 pm, "Ian Bingham"
wrote:
My average temperature graph for January (1990-2010) shows low
temperatures at the beginning and end of the month and relatively
high temperatures at mid-month. This appears to be due to the fact
that every year in January we seem to get a few days of more or less
strong SWlies which of course raises the temperature appreciably.
This has occurred at various times of the month, so the average puts
it in the middle, I suppose. For example I have as 21-year means:
Jan 1st 2.1C
Jan 15th 4.4C
Jan 31st 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

A very similar pattern here over the 20 years of my records. In fact
the 15th is the mildest day of the month with a mean temperature of
8.2C.

There are marked colder spells each side, the low points being:-

8th 6.7C
26th 6.2C - The coldest day of the winter over 20 years.

OK, so examples from two very different areas, can we
extrapolate from these two points that this is a countrywide
phenomenon
I've heard of the 'mid-December mildening' but not January.
--
Col

Bolton, Lancashire
160m asl

In article
,
Graham Easterling writes:
On Jan 7, 5:34*pm, "Ian Bingham"
wrote:
My average temperature graph for January (1990-2010) shows low temperatures
at the beginning and end of the month and relatively high temperatures at
mid-month. *This appears to be due to the fact that every year in January we
seem to get a few days of more or less strong SWlies which of course raises
the temperature appreciably. *This has occurred at various times of the
month, so the average puts it in the middle, I suppose. *For example I have
as 21-year means:
Jan 1st * 2.1C
Jan 15th *4.4C
Jan 31st * 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

A very similar pattern here over the 20 years of my records. In fact
the 15th is the mildest day of the month with a mean temperature of
8.2C.

There are marked colder spells each side, the low points being:-

8th 6.7C
26th 6.2C - The coldest day of the winter over 20 years.

Graham
Penzance

The tendency for mild and cold periods in January to occur around the
same dates in many years reminded me of the old idea of "singularities",
investigated for the UK by CEP Brooks and HH Lamb. A websearch led me to
this newsgroup's excellent FAQ developed by Martin Rowley:

http://weatherfaqs.org.uk/node/179

Brooks was looking at 1889-1940, but the mid January mildness in recent
decades would fit in very well with his identification of a "stormy"
period that occurred on average from Jan 5th - Jan 17th and peaked on
Jan 8th, which was observed in 45 years out of 52. (Assuming that in
winter stormy periods will usually be mild.)

The relative coldness around the 26th wouldn't tie in so well. Although
the period 18th - Jan 24th was generally anticyclonic, Jan 24th - Feb
1st reverted to "stormy".

Lamb's analysis was broadly similar.
--
John Hall
"I look upon it, that he who does not mind his belly,
will hardly mind anything else."
Dr Samuel Johnson (1709-84)

On Jan 7, 7:38*pm, John Hall wrote:
In article
,
*Graham Easterling writes:





On Jan 7, 5:34 pm, "Ian Bingham"
wrote:
My average temperature graph for January (1990-2010) shows low temperatures
at the beginning and end of the month and relatively high temperatures at
mid-month. This appears to be due to the fact that every year in January we
seem to get a few days of more or less strong SWlies which of course raises
the temperature appreciably. This has occurred at various times of the
month, so the average puts it in the middle, I suppose. For example I have
as 21-year means:
Jan 1st 2.1C
Jan 15th 4.4C
Jan 31st 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

A very similar pattern here over the 20 years of my records. In fact
the 15th is the mildest day of the month with a mean temperature of
8.2C.

There are marked colder spells each side, the low points being:-

8th *6.7C
26th 6.2C - The coldest day of the winter over 20 years.

Graham
Penzance

The tendency for mild and cold periods in January to occur around the
same dates in many years reminded me of the old idea of "singularities",
investigated for the UK by CEP Brooks and HH Lamb. A websearch led me to
this newsgroup's excellent FAQ developed by Martin Rowley:

http://weatherfaqs.org.uk/node/179

Brooks was looking at 1889-1940, but the mid January mildness in recent
decades would fit in very well with his identification of a "stormy"
period that occurred on average from Jan 5th - Jan 17th and peaked on
Jan 8th, which was observed in 45 years out of 52. (Assuming that in
winter stormy periods will usually be mild.)

The relative coldness around the 26th wouldn't tie in so well. Although
the period 18th - Jan 24th was generally anticyclonic, Jan 24th - Feb
1st reverted to "stormy".

Lamb's analysis was broadly similar.
--
John Hall
* * * * * * * *"I look upon it, that he who does not mind his belly,
* * * * * * * * will hardly mind anything else."
* * * * * * * * * * * * * * * * * * * * * *Dr Samuel Johnson (1709-84)- Hide quoted text -

- Show quoted text -

Lamb's 'The English Climate' was my 1st real weather book, given to me
as a present back in 1966, and it's still often referred to. At that
time I had a rather non standard home made Stevenson screen in the
back garden.

Graham
Penzance

On Jan 7, 7:35*pm, "Col" wrote:
Graham Easterling wrote:
On Jan 7, 5:34 pm, "Ian Bingham"
wrote:
My average temperature graph for January (1990-2010) shows low
temperatures at the beginning and end of the month and relatively
high temperatures at mid-month. This appears to be due to the fact
that every year in January we seem to get a few days of more or less
strong SWlies which of course raises the temperature appreciably.
This has occurred at various times of the month, so the average puts
it in the middle, I suppose. For example I have as 21-year means:
Jan 1st 2.1C
Jan 15th 4.4C
Jan 31st 2.3C

Ian Bingham,
Inchmarlo, Aberdeenshire.

A very similar pattern here over the 20 years of my records. In fact
the 15th is the mildest day of the month with a mean temperature of
8.2C.

There are marked colder spells each side, the low points being:-

8th *6.7C
26th 6.2C - The coldest day of the winter over 20 years.

OK, so examples from two very different areas, can we
extrapolate from these two points that this is a countrywide
phenomenon
I've heard of the 'mid-December mildening' but not January.
--
Col

Bolton, Lancashire
160m asl

Nonetheless in central southern England mid January has from memory
been almost unfailingly mild every year since 1988.
If one looks at wetterzentrale.de, some "mild" type or other, either
zonal or SSW winds, was present on Jan 15th on all but 4 years since
1988 - the exceptions being 1991, 1992, 2000 and 2001, which agrees
with my memory.

Over the same period, 25th Jan showed a "non mild" type (by my
interpretation of the charts) in 11 of the years since 1988, but 5th
Jan seems to have been almost equally mild with a mild type in all but
5 of the years. Until 2009/10, early Jan seemed to be equally prone to
mild weather in recent years as mid Jan, but a change of type does
seem to occur quite often later in the month.

Nick