Warm end to December

[Crispin]

There is often a warm period at the end of December, it occurs most years and is so regular there must be something responsible for this  
It happens most years.
Here is a chart of my 1995-2016 average temperatures, the late Dec peak is quite clear and is happening again this year. 
Does anyone know what causes this?

[MP-R]

Conversely, the Christmas to New Year period has also brought plentiful cold spells, as equally as mild in my lifetime. Seems a rather tenuous 'trend'.

2000, 2001, 2003, 2004, 2005, 2008, 2009, 2010 and 2014 were all cold during this period. Just the last run of years haven't been great.

[I remember Atlantic 252]

When the Atlantic wakes up, especially warm through Jan, maybe developed PV, strong jet

[D.B.]

14 hours ago, Crispin said:

There must be something responsible for this.

It is called the curse of Net Weather.

[Walsall Wood Snow]

Probably just randomness but as MP-R points out there has been cold weather between Christmas and New Year 9 out of 17 times so far since the turn of the New Millennium so actually over half. Besides I don't think the period this year looks overly mild, in fact probably average to maybe a touch below. New Year itself and the period immediately after it though has rarely been cold these days.

In fact the GFS is now predicting a snow event for much of the country next week, so maybe we'll have 10 out of 18 periods between Christmas and New Year with cold weather in the 21st century thus far. 

Edited December 22, 2017 by Walsall Wood Snow

[The PIT]

Well it looks like the last five days of this month will be on the cold side. Over all it's random I'm afraid.

[Weather-history]

17 hours ago, MP-R said:

Conversely, the Christmas to New Year period has also brought plentiful cold spells, as equally as mild in my lifetime. Seems a rather tenuous 'trend'.

2000, 2001, 2003, 2004, 2005, 2008, 2009, 2010 and 2014 were all cold during this period. Just the last run of years haven't been great.

Going further back 1996, 1995, 1993, 1992 

Infact I remember it drawing comment how often the week between Christmas and New Year was cold a few years ago.

Edited December 22, 2017 by Weather-history

[Crispin]

I'm actually talking about the period from mid-Dec up to Christmas (2nd into 3rd week) as opposed to Christmas to New Year! 
Sorry, I didn't make that clear in my original post.
The start of Dec often is typically cooler than mid-Dec then the last week of Dec it cools down again (Christmas to New Year).
Certainly, there will be natural variation and exceptions such as 2006, 07, 09 & 10 when the 3rd week was colder in relation to the previous and following week.
My point is there very often is a warmer bit, typically, in the 3rd week of Dec which shows in the longterm average and I wondered if there was anything which is known to cause this?

 

[Walsall Wood Snow]

57 minutes ago, Crispin said:

I'm actually talking about the period from mid-Dec up to Christmas (2nd into 3rd week) as opposed to Christmas to New Year! 
Sorry, I didn't make that clear in my original post.
The start of Dec often is typically cooler than mid-Dec then the last week of Dec it cools down again (Christmas to New Year).
Certainly, there will be natural variation and exceptions such as 2006, 07, 09 & 10 when the 3rd week was colder in relation to the previous and following week.
My point is there very often is a warmer bit, typically, in the 3rd week of Dec which shows in the longterm average and I wondered if there was anything which is known to cause this?

 

I could be wrong, but I suspect that could perhaps have been a common theme for much of the 20th century. We know that white Christmases have been very rare for more than a century if not a lot longer. Also in fact it seems to have always been seen as something of a romantic ideal in this country when it comes to snow at Christmas, but also seldom ever realised. It bit like bank holidays in the Spring and Summer really. We hope for fine and sunny weather, but it often ends up being a gloomy washout.