I've since confirmed that GW's stats were awry - probably is a comparison with historical mean max CET as you say.

Means for the opening 10 days provisionally place 2021 near the bottom of a long list of years since 1772 that were 1°C or below:

1814: -2.97°C
1795: -2.59°C
1820: -2.48°C
1789: -2.19°C
1864: -2.09°C
1861: -2.00°C
1841: -1.95°C
1893: -1.93°C
2010: -1.90°C
1894: -1.79°C
1811: -1.78°C
1777: -1.45°C
1879: -1.19°C
1774: -1.05°C
1891: -1.05°C
1941: -0.77°C
1784: -0.68°C
1997: -0.65°C
1963: -0.57°C
1780: -0.56°C
1887: -0.43°C
1979: -0.40°C
2009: -0.37°C
1842: -0.31°C
1802: -0.30°C
1794: -0.14°C
1850: -0.12°C
1868: -0.11°C
1799: -0.09°C

1895: 0.01°C
1985: 0.07°C
1786: 0.09°C
1970: 0.22°C
1871: 0.27°C
1778: 0.27°C
1854: 0.29°C
1931: 0.34°C
1867: 0.42°C
1815: 0.55°C
1849: 0.58°C
1918: 0.66°C
1773: 0.66°C
1908: 0.67°C
1835: 0.71°C
1921: 0.75°C
1967: 0.81°C
1833: 0.87°C
2021: 0.90°C
1940: 1.00°C

GW I must say am a little surprised that the CET was as high as that for the first ten days of 2010.

He edited the "since 1893" bit out of his post, so it looks like that wasn't true as others have suggested.

Certainly here, not only have we not had a single flake of snow this month, and only one visible hoar frost, but the lowest temperature has only been -2.3C (last night) and the lowest maximum wasn't an ice day (+0.5C, on the 7th January). Still has been a notable cold spell, but only memorable for the facts and figures, and not for what's outside the window. 

According to this link: https://www.metoffice.gov.uk/hadobs/hadcet/cetdl1772on.dat

CET First 10 days of January 2010: -1.90C

CET First 10 days of January 1979: -0.45C

CET First 10 days of January 1963: -0.57C

Damn, Stormchaser beat me to it!

That's quite something

Met Ofice Hadley      1.2c      Anomaly     -2.4c  Provisional to 10th

Metcheck                  1.37c    Anomaly     -2.79c

Netweather               1.71c    Anomaly     -2.5c

Peasedown St John   1.3c     Anomaly     -3.6c

Met Office Hadley      1.6c     Anomaly     -2.0c   Provisional to 1th

Metcheck                   1.85c   Anomaly     -2.30c

Netweather                2.16c   Anomaly    -2.05c

Peasedown St John   1.8c     Anomaly    -3.1c.     

Thanks for that detail James. Amazing, in fact, to see 1940's first 10 so far down the table.

Reminds us again how the whole pattern can shift- edit: 1987 too.

I guess we'll be above 2 in a day or so, but if the models keep showing the same scene (although there are hiccups possibly developing) we could drop to close to zero by month's end. That would be an interesting start to the 2021 profile.

This makes more sense . Very rare for GW to get it wrong though.

Met Office Hadley        1.9c       Anomaly      -1.7c Provisional to 12th

Metcheck                      1.87c    Anomaly      -2.28c

Netweather                   2.42c    Anomaly      -1.79c

Peasedown St John     2.3c      Anomaly       -2.6c.                  

Met Office Hadley        2.1c       Anomaly      -1.4c provisional to 13th

Metcheck                     2.06c     Anomaly      -2.10c

Netweather                  2.59c     Anomaly      -1.62c

Peasedown St John     2.95c     Anomaly      -1.95c. 

Met Office Hadley. 2•3c. Anomaly -1•2°c Provisional to 14th.
Metcheck. 1.91c Anomaly. -2.16c
Netweather 2.71c. Anomaly -1.5c
Peasedown St John. 3.1c. Anomaly. -1.8c.

Where on Earth will the CET go during the final third of the month?

The outlook is almost binary; south-shifted Atlantic storms look to scoop up some exceptionally mild air ahead of them which then clashes with cold polar air along a boundary that looks likely to waver near or across the UK.

The CET zone could see numerous bouts of snowfall with temperatures becoming very cold as feedbacks kick in.

OR it could be bathed in air capable of lifting temperatures toward the mid-teens!

...or perhaps it will be a wild mix of the two. Some runs are managing that, with temperatures oscillating rapidly between freezing and balmy.

Potential for a strong month mean temperature gradient between the CET zone and the far south of England; even as of 14th there's close to a whole degree Celsius of difference between the CET and my local mean.

Met Office Hadley        2.3c      Anomaly     -1.2c Provisional to 15th

Metcheck                     1.93c    Anomaly     -2.23c

Netweather                  2.59c    Anomaly     -1.62c

Peasedown St John     2.65c    Anomaly      -2.23c.      

Met Office Hadley         2.4c      Anomaly     -1.1c provisional to 1th

Metcheck                      2.17c    Anomaly      -2.02c

Netweather                   2.76c    Anomaly      -1.45c

Peasedown St John     3.2c       Anomaly       -1.7c

The local area of 8 stations  2.88c.

Met Office Hadley       2.6c       Anomaly      -0.9c Provisional to 17th

Metcheck                    2.4c       Anomaly      -1.92c

Netweather                 2.9c       Anomaly      -1.31c

Peasedown St John    3.3c      Anomaly       -1.6c  

Met Office Hadley      2.8c     Anomaly    -0.7c Provisional to 18th

Metcheck                   2.52c   Anomaly    -1.63c

Netweather                3.04c   Anomaly    -1.17c

Peasedown St John   3.65c   Anomaly    -1.25c.     

Sorry for the confusion on the data about the early days of this month. I was incorrectly looking at the maximum data.

Here is the latest CET tracker. We are in a brief milder spell before it turns cold again at the end of the week. The final 6 days of the month are looking warm though. That could be enough to bring the CET up to 3.77C. Currently my estimate is running more than 0.4C below Hadley so there could be a large downward correction this month. Could be the coldest month since Feb 2018.

Chart 1

Chart 2

I’m reasonably happy with my 3.2c guess but I am wondering if I should have stuck with my original thoughts of 2.3c.  I have a feeling the month will end somewhere in between.