2023 CET - all 12 months above 1961-1990 average?

[WYorksWeather]

Thought I'd start this thread. As mentioned a while ago, there's some chance that we could have a unique record this year. No calendar year in the entire CET record has ever been above the 1961-1990 average for every month. The following years have had 11 months above the 1961-1990 average: 1781, 1834, 1945, 1949, 1959, 1999,  2003, 2006, 2014, and 2022. Last year we fell just short, with a below average December CET.

So far, every month this year has been above the 1961-1990 average. Given that we've got a mild next few days to come, and a CET around 3C above average so far, it looks almost certain that we're going to maintain the run in October.

It will be interesting to see if this year will finally be the year it happens. Too early for much model guidance into November, so probably not much further to update at this point. 

 

[Frigid]

Models are suggesting a blocked November, the latest met update also mention the chance of cold easterlies. Being the met are never bullish on cold till at a closer timeframe there could be a chance of it being the first month of the year to come under the 61-90 average. Last year, it was looking likely but of course December came in with a bang being the coldest since 2010.. though that was a mere coincidence. Could it happen again?

[Metwatch]

It's better to compare to the 1991-2020 average rather than older average, what almost all countries do now, Met Office CET the only one behind really, it's more representative of current climate.

That makes 3 months below the new average this year (April, July, August). Not disagreeing with your original post, but important to take note of. 

Edited October 18, 2023 by Metwatch

[WYorksWeather]

23 minutes ago, Metwatch said:

It's better to compare to the 1991-2020 average rather than older average, what almost all countries do now, Met Office CET the only one behind really, it's more representative of current climate.

That makes 3 months below the new average this year (April, July, August). Not disagreeing with your original post, but important to take note of. 

I agree that for most purposes recent averages are better.

I think it depends what you're looking at, though. If you compare to more recent averages you can't see changes from the past - it's extremely unlikely any year will exceed the average for the preceding three decades in every month if you use a rolling time window - in 20 years, say, we might see a year that exceeds 1991-2020 for every month, but by then the average will have moved on to 2011-2040.

This would still be an unprecedented event in terms of persistent warmth - you could define it in terms of the 1991-2020 average just as easily - first year to have no month drop more than X degrees below the 1991-2020 average (don't remember how far below April, July and August were on the CET for 1991-2020). Of course it doesn't quite have the same ring to it!

In any case, I still thought it was worth drawing attention to the fact that this might finally happen, given that there have been several near misses. Of course all to play for with November and December.

[WYorksWeather]

36 minutes ago, Frigid said:

Models are suggesting a blocked November, the latest met update also mention the chance of cold easterlies. Being the met are never bullish on cold till at a closer timeframe there could be a chance of it being the first month of the year to come under the 61-90 average. Last year, it was looking likely but of course December came in with a bang being the coldest since 2010.. though that was a mere coincidence. Could it happen again?

Given trends in recent years, it seems like the average number of months above 1961-1990 is something like 9-10, so on that basis you'd probably say that a priori, the chance of two consecutive months coming out below average is somewhere around 1/4 or 1/3. So I still think it's possible we'll avoid this for another year, but probably more likely than not that it will happen, in my opinion.

[Summer of 95]

Which month in 1999 was below? None of them seemed cool that year, even if only July and maybe September to some extent were notably warm.

2003- October I presume, 2006 March and 2014 August?

[LetItSnow!]

1 hour ago, Summer of 95 said:

Which month in 1999 was below? None of them seemed cool that year, even if only July and maybe September to some extent were notably warm.

2003- October I presume, 2006 March and 2014 August?

June 1999 was the only below average month with a C.E.T of 13.8. 

[damianslaw]

Mmm jury out on November I think this year..

[Roger J Smith]

The 1961-90 normals can be back-calculated for 2022 actual data as

3.9 _ 3.8 _ 5.7 _ 7.9 _ 11.2 _ 14.1 _ 16.0 _ 15.8 _ 13.5 _ 10.5 _ 6.5 _ 4.5

but for 2021 actual data you get

3.8 _ 3.8 _ 5.7 _ 7.8 _ 11.2 _ 14.1 _ 15.9 _ 15.7 _ 13.6 _ 10.6 _ 6.4 _ 4.5

Just wondering, apparently in one decimal there are rounding issues and so a few of those are off by 0.1 in any given year, and if so, what are the 1961-90 normals, and according to what source? 

I would say that looks to be a fairly cold year by present standards. 

1834 was close to being warmer for all twelve:

1834 _ 7.1 _5.6 _7.1 _7.7 _13.0 _15.4 _16.9 _16.2 _13.8 _10.6 _6.7 _5.6 __(10.5)

April was a bit below and October near a tie if possibly above. At 10.5 it was warmest year on record (tied 1733 and later 1921) until beaten in 1949 (10.6), a year with 10/12 (failed only march plus a tie in may or 0.1 above?). A few years in 1730s scored 9 or 10 out of 12 above (depending on exactly what 1961-90 values are correct). It seems a lot of promising years in the past failed to beat October. 1868 (10.4) failed only Oct and Nov and scored 10/12. 1921 (10.5) failed Aug and Nov. 

After a very cold Jan, 1945 (and also 1959) passed the other eleven. 

1989 and 1990 each failed two, 1989 Apr and Nov, 1990 Sep and Dec. 

1995 failed two (mar and dec) and has a tie (I think) for Sep. 

1999 as noted missed on one (June) and may be tied for Oct at 10.6. 

Failing only two months becomes fairly common in years after 1999; years with one failure include 2003, 2014 and 2022. (2003 also has a tie, I think, for Dec). Not sure if 2017 is 10-2, 11-1 or has one or two ties? (Aug 15.7 Sep 13.6 look like near ties)

 

 

 

[Weather-history]

What makes it tricky to achieve to get all months of a year, all above or all below  long term averages are cuckoos,  months that buck the trend of the period and seem to pop up out of nowhere.  December 2022 was one.

Even 1740 had one,  the September. That's looking at it from the other side of coin, though.

 

[Roger J Smith]

Every month of 1879 was below the 1961-1990 normals:

-0.7 _3.1 _4.7 _5.7 _8.9 _12.9 _13.6 _14.5 _12.6 _8.9 _4.1 _0.7 __ (7.4)

and was also below existing 30-year normals for 1841-1870:

3.4 _3.9 _5.2 _8.2 _11.2 _14.4 _15.8 _ 15.4 _13.2 _9.6 _5.7 _4.3 __ (9.2)

 

Edited October 19, 2023 by Roger J Smith

[Roger J Smith]

It's interesting to see normals from 1841-1870 are warmer for Feb, Apr, (equal may), and June compared to 1961-1990. Oct and Nov were significantly warmer (in 1961-90) but Dec and Jan, July to Sep, not very different, a bit warmer.

[rwtwm]

11 hours ago, Metwatch said:

It's better to compare to the 1991-2020 average rather than older average, what almost all countries do now, Met Office CET the only one behind really, it's more representative of current climate.

That makes 3 months below the new average this year (April, July, August). Not disagreeing with your original post, but important to take note of. 

They are two different questions IMO. Comparing to more modern average is checking how big a departure the temperature is from what one might expect given AGW. 

The question here is looking at the departure from a long term average, therefore measuring the impact of a warming climate. I think both are relevant, and to continually update the reference mean without showing the long term context is only telling half the story.

 

[Roger J Smith]

30-yr period _____ JAN __ FEB __ MAR __ APR __ MAY __ JUN __ JUL __ AUG __ SEP __ OCT __ NOV __ DEC__YEAR

 

(all data 1659-2023)_3.3 ___3.9 ___5.3 ___7.9 __ 11.2 __ 14.3 __ 16.0 __ 15.6 __ 13.3 ___9.7 ___6.1 ___4.1 __ 9.2

 

1661-1690 _______ 2.9 ___3.1 ___4.8 ___7.4 __ 11.0 __ 14.3 __ 15.8 __ 15.3 __ 12.8 ___9.4 ___5.7 ___3.4 __ 8.8

1671-1700________2.6 ___2.6 ___4.4 ___7.1 __ 10.7 __ 13.9 __ 15.5 __ 14.9 __ 12.3 ___9.0 ___5.3 ___3.3 __ 8.5

1681-1710________2.4 ___3.0 ___4.5 ___7.3 __ 10.8 __ 13.9 __ 15.5 __ 15.3 __ 12.6 ___9.0 ___5.6 ___4.0 __ 8.6

1691-1720________2.6 ___3.3 ___4.7 ___7.4 __ 10.7 __ 14.0 __ 15.8 __ 15.5 __ 12.9 ___9.1 ___5.8 ___3.8 __ 8.8

1701-1730________3.1 ___3.8 ___5.1 ___7.9 __ 11.3 __ 14.4 __ 15.9 __ 15.8 __ 13.6 ___9.5 ___6.4 ___4.0 __ 9.2

1711-1740________3.4 ___4.0 ___5.4 ___8.1 __ 11.2 __ 14.6 __ 16.0 __ 15.7 __ 13.8 ___9.7 ___6.2 ___4.1 __ 9.3

1721-1750________3.4 ___3.9 ___5.2 ___7.8 __ 11.4 __ 14.5 __ 16.0 __ 15.9 __ 14.0 ___9.6 ___6.3 ___4.2 __ 9.3

1731-1760________3.3 ___3.8 ___5.2 ___7.7 __ 11.2 __ 14.5 __ 16.1 __ 15.8 __ 13.8 ___9.4 ___5.8 ___4.2 __ 9.2

1741-1770________2.9 ___3.7 ___4.8 ___7.6 __ 11.2 __ 14.3 __ 16.0 __ 15.7 __ 13.6 ___9.2 ___5.7 ___3.9 __ 9.0

1751-1780________2.4 ___3.7 ___5.3 ___7.9 __ 11.2 __ 14.5 __ 16.1 __ 15.8 __ 13.4 ___9.3 ___5.6 ___3.7 __ 9.0

1761-1790________2.4 ___3.7 ___4.8 ___7.9 __ 11.5 __ 14.6 __ 16.1 __ 15.9 __ 13.3 ___9.2 ___5.5 ___3.7 __ 9.0

1771-1800________2.4 ___3.8 ___4.9 ___8.1 __ 11.4 __ 14.7 __ 16.3 __ 15.9 __ 13.3 ___9.2 ___5.5 ___3.5 __ 9.1

1781-1810________2.9 ___3.8 ___4.6 ___8.0 __ 11.5 __ 14.6 __ 16.1 __ 15.8 __ 13.2 ___9.4 ___5.3 ___3.2 __ 9.0

1791-1820________2.5 ___4.0 ___5.1 ___8.0 __ 11.2 __ 14.2 __ 15.9 __ 15.6 __ 13.1 ___9.5 ___5.5 ___3.2 __ 9.0

1801-1830________2.4 ___3.9 ___5.5 ___7.9 __ 11.4 __ 14.2 __ 15.8 __ 15.8 __ 13.1 ___9.8 ___5.9 ___3.6 __ 9.1

1811-1840________2.3 ___4.0 ___5.4 ___7.9 __ 11.4 __ 14.4 __ 15.7 __ 15.6 __ 13.0 ___9.8 ___6.1 ___4.0 __ 9.1

1821-1850________2.6 ___3.9 ___5.5 ___8.0 __ 11.6 __ 14.7 __ 15.7 __ 15.3 __ 13.0 ___9.6 ___6.3 ___4.5 __ 9.2

1831-1860________3.2 ___3.7 ___5.2 ___7.8 __ 11.2 __ 14.6 __ 15.7 __ 15.4 __ 13.0 ___9.6 ___5.8 ___4.3 __ 9.1

1841-1870________3.4 ___3.9 ___5.2 ___8.2 __ 11.2 __ 14.4 __ 15.8 __ 15.4 __ 13.2 ___9.6 ___5.7 ___4.3 __ 9.2

1851-1880________3.7 ___4.2 ___5.2 ___8.2 __ 10.8 __ 14.2 __ 15.9 __ 15.6 __ 13.2 ___9.7 ___5.3 ___4.1 __ 9.2

1861-1890________3.5 ___4.5 ___5.1 ___8.1 __ 10.9 __ 14.1 __ 15.8 __ 15.4 __ 13.2 ___9.3 ___5.7 ___3.8 __ 9.1

1871-1900________3.4 ___4.2 ___5.2 ___7.9 __ 10.7 __ 14.2 __ 15.8 __ 15.5 __ 13.1 ___9.0 ___6.1 ___3.7 __ 9.1

1881-1910________3.5 ___3.9 ___5.1 ___7.7 __ 10.9 __ 14.1 __ 15.7 __ 15.2 __ 13.1 ___9.3 ___6.3 ___4.0 __ 9.1

1891-1920________3.7 ___4.1 ___5.3 ___7.9 __ 11.3 __ 14.1 __ 15.7 __ 15.4 __ 13.1 ___9.4 ___6.2 ___4.5 __ 9.2

1901-1930________4.2 ___4.2 ___5.5 ___8.0 __ 11.3 __ 13.8 __ 15.8 __ 15.2 __ 13.1 ___9.8 ___5.8 ___4.5 __ 9.2

1911-1940________4.2 ___4.3 ___5.7 ___8.2 __ 11.5 __ 14.2 __ 15.9 __ 15.6 __ 13.3 ___9.6 ___6.2 ___4.6 __ 9.4

1921-1950________3.9 ___4.2 ___5.9 ___8.0 __ 11.3 __ 14.4 __ 16.3 __ 15.9 __ 13.6 __10.0 ___6.4 ___4.5 __ 9.5

1931-1960________3.5 ___3.9 ___5.9 ___8.1 __ 11.5 __ 14.6 __ 16.2 __ 16.0 __ 13.7 __10.1 ___6.8 ___4.7 __ 9.6

1941-1970________3.3 ___3.6 ___5.7 ___8.1 __ 11.4 __ 14.5 __ 16.0 __ 15.7 __ 13.7 __10.6 ___6.6 ___4.4 __ 9.5

1951-1980________3.6 ___3.7 ___5.6 ___8.0 __ 11.3 __ 14.3 __ 15.9 __ 15.6 __ 13.6 __10.5 ___6.6 ___4.7 __ 9.4

1961-1990________3.8 ___3.8 ___5.7 ___7.9 __ 11.2 __ 14.2 __ 16.1 __ 15.8 __ 13.6 __10.6 ___6.6 ___4.7 __ 9.5

1971-2000________4.2 ___4.2 ___6.3 ___8.1 __ 11.3 __ 14.1 __ 16.5 __ 16.2 __ 13.7 __10.4 ___6.9 ___5.1 __ 9.7

1981-2010________4.4 ___4.4 ___6.6 ___8.5 __ 11.7 __ 14.4 __ 16.7 __ 16.4 __ 14.0 __10.7 ___7.1 ___4.6 __10.0

1991-2020 _______ 4.7 __ 4.9 __ 6.7 ___ 9.0 __ 11.9 __ 14.7 __ 16.8 __ 16.5 __ 14.2 __10.9 __ 7.4 __ 5.0 __ 10.2

 

(calculated by me a few years ago using CET legacy, could be a few adjusted values in recent decades, v2 is a bit cooler in 1970s and 1980s, don't expect big adjustments in earlier decades). 

 

[WYorksWeather]

10 hours ago, Roger J Smith said:

The 1961-90 normals can be back-calculated for 2022 actual data as

3.9 _ 3.8 _ 5.7 _ 7.9 _ 11.2 _ 14.1 _ 16.0 _ 15.8 _ 13.5 _ 10.5 _ 6.5 _ 4.5

but for 2021 actual data you get

3.8 _ 3.8 _ 5.7 _ 7.8 _ 11.2 _ 14.1 _ 15.9 _ 15.7 _ 13.6 _ 10.6 _ 6.4 _ 4.5

Just wondering, apparently in one decimal there are rounding issues and so a few of those are off by 0.1 in any given year, and if so, what are the 1961-90 normals, and according to what source? 

I would say that looks to be a fairly cold year by present standards. 

1834 was close to being warmer for all twelve:

1834 _ 7.1 _5.6 _7.1 _7.7 _13.0 _15.4 _16.9 _16.2 _13.8 _10.6 _6.7 _5.6 __(10.5)

April was a bit below and October near a tie if possibly above. At 10.5 it was warmest year on record (tied 1733 and later 1921) until beaten in 1949 (10.6), a year with 10/12 (failed only march plus a tie in may or 0.1 above?). A few years in 1730s scored 9 or 10 out of 12 above (depending on exactly what 1961-90 values are correct). It seems a lot of promising years in the past failed to beat October. 1868 (10.4) failed only Oct and Nov and scored 10/12. 1921 (10.5) failed Aug and Nov. 

After a very cold Jan, 1945 (and also 1959) passed the other eleven. 

1989 and 1990 each failed two, 1989 Apr and Nov, 1990 Sep and Dec. 

1995 failed two (mar and dec) and has a tie (I think) for Sep. 

1999 as noted missed on one (June) and may be tied for Oct at 10.6. 

Failing only two months becomes fairly common in years after 1999; years with one failure include 2003, 2014 and 2022. (2003 also has a tie, I think, for Dec). Not sure if 2017 is 10-2, 11-1 or has one or two ties? (Aug 15.7 Sep 13.6 look like near ties)

 

 

 

My method was to take the daily figures for 1961-1990 and compute averages by month. I used a strict test, to only allow months with positive anomalies. For example, 2017 shows with rounded anomalies of 0.0 for August and September, and above average for all other months, but both of those are actually negative. This was calculated using the latest version of CET i.e. version 2.0.1.0.

Month 1961-1990 average

1 3.81

2 3.80

3 5.67

4 7.88

5 11.2

6 14.1

7 16.0

8 15.8

9 13.6

10 10.5

11 6.43

12 4.54

[WYorksWeather]

10 hours ago, Weather-history said:

What makes it tricky to achieve to get all months of a year, all above or all below  long term averages are cuckoos,  months that buck the trend of the period and seem to pop up out of nowhere.  December 2022 was one.

Even 1740 had one,  the September. That's looking at it from the other side of coin, though.

 

It all comes down to probability in the end. If you assume the temperature anomaly for each month is statistically independent (i.e. month to month correlation is zero, or approximately zero), then even with a very high probability of each month being above average, like 75%, the overall chance of getting a whole year with no below average months is still only 3%. For this event to be regular, we'd need something like a 90% probability for each month, which would give odds of around 30%.

It's probably not entirely true that months are statistically independent of one another, but it's also unlikely that the correlation is very high, otherwise you'd be able to make long range forecasts very easily!

[sunny_vale]

On 19/10/2023 at 19:58, Roger J Smith said:

30-yr period _____ JAN __ FEB __ MAR __ APR __ MAY __ JUN __ JUL __ AUG __ SEP __ OCT __ NOV __ DEC__YEAR

 

(all data 1659-2023)_3.3 ___3.9 ___5.3 ___7.9 __ 11.2 __ 14.3 __ 16.0 __ 15.6 __ 13.3 ___9.7 ___6.1 ___4.1 __ 9.2

 

1661-1690 _______ 2.9 ___3.1 ___4.8 ___7.4 __ 11.0 __ 14.3 __ 15.8 __ 15.3 __ 12.8 ___9.4 ___5.7 ___3.4 __ 8.8

1671-1700________2.6 ___2.6 ___4.4 ___7.1 __ 10.7 __ 13.9 __ 15.5 __ 14.9 __ 12.3 ___9.0 ___5.3 ___3.3 __ 8.5

1681-1710________2.4 ___3.0 ___4.5 ___7.3 __ 10.8 __ 13.9 __ 15.5 __ 15.3 __ 12.6 ___9.0 ___5.6 ___4.0 __ 8.6

1691-1720________2.6 ___3.3 ___4.7 ___7.4 __ 10.7 __ 14.0 __ 15.8 __ 15.5 __ 12.9 ___9.1 ___5.8 ___3.8 __ 8.8

1701-1730________3.1 ___3.8 ___5.1 ___7.9 __ 11.3 __ 14.4 __ 15.9 __ 15.8 __ 13.6 ___9.5 ___6.4 ___4.0 __ 9.2

1711-1740________3.4 ___4.0 ___5.4 ___8.1 __ 11.2 __ 14.6 __ 16.0 __ 15.7 __ 13.8 ___9.7 ___6.2 ___4.1 __ 9.3

1721-1750________3.4 ___3.9 ___5.2 ___7.8 __ 11.4 __ 14.5 __ 16.0 __ 15.9 __ 14.0 ___9.6 ___6.3 ___4.2 __ 9.3

1731-1760________3.3 ___3.8 ___5.2 ___7.7 __ 11.2 __ 14.5 __ 16.1 __ 15.8 __ 13.8 ___9.4 ___5.8 ___4.2 __ 9.2

1741-1770________2.9 ___3.7 ___4.8 ___7.6 __ 11.2 __ 14.3 __ 16.0 __ 15.7 __ 13.6 ___9.2 ___5.7 ___3.9 __ 9.0

1751-1780________2.4 ___3.7 ___5.3 ___7.9 __ 11.2 __ 14.5 __ 16.1 __ 15.8 __ 13.4 ___9.3 ___5.6 ___3.7 __ 9.0

1761-1790________2.4 ___3.7 ___4.8 ___7.9 __ 11.5 __ 14.6 __ 16.1 __ 15.9 __ 13.3 ___9.2 ___5.5 ___3.7 __ 9.0

1771-1800________2.4 ___3.8 ___4.9 ___8.1 __ 11.4 __ 14.7 __ 16.3 __ 15.9 __ 13.3 ___9.2 ___5.5 ___3.5 __ 9.1

1781-1810________2.9 ___3.8 ___4.6 ___8.0 __ 11.5 __ 14.6 __ 16.1 __ 15.8 __ 13.2 ___9.4 ___5.3 ___3.2 __ 9.0

1791-1820________2.5 ___4.0 ___5.1 ___8.0 __ 11.2 __ 14.2 __ 15.9 __ 15.6 __ 13.1 ___9.5 ___5.5 ___3.2 __ 9.0

1801-1830________2.4 ___3.9 ___5.5 ___7.9 __ 11.4 __ 14.2 __ 15.8 __ 15.8 __ 13.1 ___9.8 ___5.9 ___3.6 __ 9.1

1811-1840________2.3 ___4.0 ___5.4 ___7.9 __ 11.4 __ 14.4 __ 15.7 __ 15.6 __ 13.0 ___9.8 ___6.1 ___4.0 __ 9.1

1821-1850________2.6 ___3.9 ___5.5 ___8.0 __ 11.6 __ 14.7 __ 15.7 __ 15.3 __ 13.0 ___9.6 ___6.3 ___4.5 __ 9.2

1831-1860________3.2 ___3.7 ___5.2 ___7.8 __ 11.2 __ 14.6 __ 15.7 __ 15.4 __ 13.0 ___9.6 ___5.8 ___4.3 __ 9.1

1841-1870________3.4 ___3.9 ___5.2 ___8.2 __ 11.2 __ 14.4 __ 15.8 __ 15.4 __ 13.2 ___9.6 ___5.7 ___4.3 __ 9.2

1851-1880________3.7 ___4.2 ___5.2 ___8.2 __ 10.8 __ 14.2 __ 15.9 __ 15.6 __ 13.2 ___9.7 ___5.3 ___4.1 __ 9.2

1861-1890________3.5 ___4.5 ___5.1 ___8.1 __ 10.9 __ 14.1 __ 15.8 __ 15.4 __ 13.2 ___9.3 ___5.7 ___3.8 __ 9.1

1871-1900________3.4 ___4.2 ___5.2 ___7.9 __ 10.7 __ 14.2 __ 15.8 __ 15.5 __ 13.1 ___9.0 ___6.1 ___3.7 __ 9.1

1881-1910________3.5 ___3.9 ___5.1 ___7.7 __ 10.9 __ 14.1 __ 15.7 __ 15.2 __ 13.1 ___9.3 ___6.3 ___4.0 __ 9.1

1891-1920________3.7 ___4.1 ___5.3 ___7.9 __ 11.3 __ 14.1 __ 15.7 __ 15.4 __ 13.1 ___9.4 ___6.2 ___4.5 __ 9.2

1901-1930________4.2 ___4.2 ___5.5 ___8.0 __ 11.3 __ 13.8 __ 15.8 __ 15.2 __ 13.1 ___9.8 ___5.8 ___4.5 __ 9.2

1911-1940________4.2 ___4.3 ___5.7 ___8.2 __ 11.5 __ 14.2 __ 15.9 __ 15.6 __ 13.3 ___9.6 ___6.2 ___4.6 __ 9.4

1921-1950________3.9 ___4.2 ___5.9 ___8.0 __ 11.3 __ 14.4 __ 16.3 __ 15.9 __ 13.6 __10.0 ___6.4 ___4.5 __ 9.5

1931-1960________3.5 ___3.9 ___5.9 ___8.1 __ 11.5 __ 14.6 __ 16.2 __ 16.0 __ 13.7 __10.1 ___6.8 ___4.7 __ 9.6

1941-1970________3.3 ___3.6 ___5.7 ___8.1 __ 11.4 __ 14.5 __ 16.0 __ 15.7 __ 13.7 __10.6 ___6.6 ___4.4 __ 9.5

1951-1980________3.6 ___3.7 ___5.6 ___8.0 __ 11.3 __ 14.3 __ 15.9 __ 15.6 __ 13.6 __10.5 ___6.6 ___4.7 __ 9.4

1961-1990________3.8 ___3.8 ___5.7 ___7.9 __ 11.2 __ 14.2 __ 16.1 __ 15.8 __ 13.6 __10.6 ___6.6 ___4.7 __ 9.5

1971-2000________4.2 ___4.2 ___6.3 ___8.1 __ 11.3 __ 14.1 __ 16.5 __ 16.2 __ 13.7 __10.4 ___6.9 ___5.1 __ 9.7

1981-2010________4.4 ___4.4 ___6.6 ___8.5 __ 11.7 __ 14.4 __ 16.7 __ 16.4 __ 14.0 __10.7 ___7.1 ___4.6 __10.0

1991-2020 _______ 4.7 __ 4.9 __ 6.7 ___ 9.0 __ 11.9 __ 14.7 __ 16.8 __ 16.5 __ 14.2 __10.9 __ 7.4 __ 5.0 __ 10.2

 

(calculated by me a few years ago using CET legacy, could be a few adjusted values in recent decades, v2 is a bit cooler in 1970s and 1980s, don't expect big adjustments in earlier decades). 

 

Really interesting looking through that table. I'd bag the 1771-1800 - amongst the coldest winters and summers that sit between 1961-1990 & 1971-2000. Was there perhaps a more continental influence at that time?

Edited October 21, 2023 by sunny_vale

[Summer8906]

It would certainly be ironic if 2023, a year which to me has been defined more by persistent dull, wet weather than warmth, would be the only year to end up with all 12 months above the average, even if that is the older 61-90 average (which of course is biased by the unusually cold 1960s).

But I guess it's a sign of a lack of really cold airmasses rather than anything else: this year has been notable for a lack of northerly outbreaks.

Edited October 21, 2023 by Summer8906

[Summer8906]

11 hours ago, sunny_vale said:

Really interesting looking through that table. I'd bag the 1771-1800 - amongst the coldest winters and summers that sit between 1961-1990 & 1971-2000. Was there perhaps a more continental influence at that time?

Also interesting to note how little the summer months have risen compared to the rest of the year. A very marginal 0.1 rise between 1981-2010 and 1991-2020 in July and August compared to some serious rises elsewhere - which backs up the observation that many high summer periods of late have been disappointing.

[Bradley in Kent]

On 21/10/2023 at 20:31, Summer8906 said:

Also interesting to note how little the summer months have risen compared to the rest of the year. A very marginal 0.1 rise between 1981-2010 and 1991-2020 in July and August compared to some serious rises elsewhere - which backs up the observation that many high summer periods of late have been disappointing.

I suppose with 1981 - 2010 vs. 1991 - 2020 you're looking at how the 1980s compared to the 2010s and how those decades skew the average both datasets sharing the 1990s and 2000s  

I wasn't alive but looking at graphs it appears the 80s had some proper summers and a fair scattering of cold winters as well. (On paper 1980s looks like the best decade if extremes and a more continental vibe are your thing)

Looking at 2011 to 2020, it was the near opposite  being very 'Atlantic' in comparison with some very mild winters and drab high summers. 

If this year does end up being a 12 monther, it wouldn't surprise me as temperature records just keep falling. Before December 2022, the previous below average month was 19 months before in May 2021. So we've gone for over a period of 12 months already, just a matter of time before it tallys with a calendar year.

[WYorksWeather]

3 hours ago, Bradley in Kent said:

I suppose with 1981 - 2010 vs. 1991 - 2020 you're looking at how the 1980s compared to the 2010s and how those decades skew the average both datasets sharing the 1990s and 2000s  

I wasn't alive but looking at graphs it appears the 80s had some proper summers and a fair scattering of cold winters as well. (On paper 1980s looks like the best decade if extremes and a more continental vibe are your thing)

Looking at 2011 to 2020, it was the near opposite  being very 'Atlantic' in comparison with some very mild winters and drab high summers. 

If this year does end up being a 12 monther, it wouldn't surprise me as temperature records just keep falling. Before December 2022, the previous below average month was 19 months before in May 2021. So we've gone for over a period of 12 months already, just a matter of time before it tallys with a calendar year.

Interestingly though, the 1991-2020 period is warmer for every month than 1981-2020, though admittedly the changes in summer are fairly marginal. Probably quite a skew upwards from one or two particularly warm summers, especially 2018 which stands out. Again wasn't alive in the 80s so can't speak more subjectively about how the 1980s summers compare to the 2010s.

[WYorksWeather]

In relation to where this is looking into November, I'd say there is perhaps a higher than normal chance of seeing something below average. The ECM meteogram for Sheffield is broadly below average by day, and around average by night. If this verified, I imagine we'd be near-normal on 1961-1990. We'd still need a cold spell later on to get a below average month, but it would open the door to avoiding the title of this thread for another year. The last two months have both started extremely mild and therefore scuppered any chances very early on. The same doesn't look likely to happen in November at the moment.

[Summer8906]

13 hours ago, Bradley in Kent said:

I suppose with 1981 - 2010 vs. 1991 - 2020 you're looking at how the 1980s compared to the 2010s and how those decades skew the average both datasets sharing the 1990s and 2000s  

I wasn't alive but looking at graphs it appears the 80s had some proper summers and a fair scattering of cold winters as well. (On paper 1980s looks like the best decade if extremes and a more continental vibe are your thing)

Looking at 2011 to 2020, it was the near opposite  being very 'Atlantic' in comparison with some very mild winters and drab high summers. 

If this year does end up being a 12 monther, it wouldn't surprise me as temperature records just keep falling. Before December 2022, the previous below average month was 19 months before in May 2021. So we've gone for over a period of 12 months already, just a matter of time before it tallys with a calendar year.

I was alive (late childhood / teenage) in the 80s and the main feature of the 80s (well, 1981-90 in this context) was colder, often significantly colder, and more blocked winters than now. Four of the 10 winters from 1981-90 (1982, 1985, 1986, and 1987 - Jan years) featured prolonged cold and really serious snow sometime in the winter. And one of the others (1983) featured a smaller, but more significant cold spell. Decembers were generally mild in this period though, except 1981 which was extremely cold and 1990 which was fairly cold. Interestingly 1981-2010 begins and ends with two extreme Decembers which appears to particularly drag the average down, though cold Decembers seemed to be relatively common in the 90s and 00s in general.

Springs in the 80s were generally colder, cloudier and more unsettled than now. Summers were cooler by night (but perhaps comparable by day) with similar cloud levels to now - most 80s summers were changeable though 1981-90 did feature four good ones (1983, 1984, 1989, 1990) compared to three from 2011-20 (2013, 2014, 2018). However the 80s summers seemed to have more NW-lies and less SW-lies than the 10s summers.

Autumn and early winter seemed to feature less extreme wet, cyclonic weather from 1981-90 compared to recently, with some exceptions (October 1987 obviously, and one or two others).  Even in 1987 the really unsettled weather was restricted to about two weeks. Benign autumns seemed to be rather more common in the 81-90 period with several instances of benign Novembers (1981, 1983, 1985, 1987, 1988, 1989 and 1990).

 

Edited October 30, 2023 by Summer8906

[WYorksWeather]

Now looking that 11/11 is a dead cert, November at +2C to around the 22nd, no chance of falling below.

All eyes on December now - in a repeat of last year's situation, do we finally see this enigma go, or do we get a colder than average December?

[WYorksWeather]

Now reviving this thread. I'll be tracking throughout December. Based on the last few years, we have an a priori chance of around 80% for any given month to be above average on 1961-1990. So as a starting point, you'd predict that this enigma is likely to go this year.

But, as we all know, December has started with a cold spell. I'm going to update this fairly regularly, and give my assessment of where I think we're at.

So, with that being said, our target to beat is 4.5C, so I'll set 4.6C as the minimum required.

From my post in the December CET thread, we have the 10-year trailing average (2013-2022) at 5.9C, and the 30-year trailing average (1993-2022) at 4.9C.

So, we can therefore calculate using today's average, substitute in the 10-year and 30-year averages, then see what happens. I'll do two versions - a naive calculation, then one based on an outlook for the next few days which should be a little more realistic.

Naive version - averages only

Today's average: -0.5C (1 day)

10-year average for rest of December: (-0.5 * 1 + 5.9 * 30) / 31 = 5.7C

30-year average:  (-0.5 * 1 + 4.9 * 30) / 31 = 4.7C

Assumed average to Dec 5th

Based on model output, a reasonable guess for the running average to the 5th is probably around 0C, give or take. Substituting that in, we get the following.

10-year average: (0 * 5 + 5.9 * 26) / 31 = 4.9C

30-year average:  (0 * 5 + 4.9 * 26) / 31 =  4.1C

Conclusion

Based on a short term outlook, this looks like it will be a very interesting thing to keep an eye on, with a real chance of a second December miss in a row! All eyes on the modelling beginning to firm up for week 2.

My (subjective) chance of the record going as of today is going to be set at 60%.