Annual CET

[WYorksWeather]

 summer blizzard Any finish below 7C or so would require December to be milder than November. Not unheard of, but would be quite unusual.

I'd probably put it at about a 20% chance at the moment of finishing at or above 11C, but dropping rapidly if we don't see a strong mild signal develop over the next week or so.

[SqueakheartLW]

Currently touch and go as to whether we get our 3rd 11C year in a row. We are currently provisionally as of 25/12/2024 at 11.048C for the rolling annual mean figure with only 6 more crucial daily means to add.

At present we would require an average daily mean CET values of 8.1C for the final 6 days of the year to achieve exactly 11.000C to 3 decimal places on my current calculations. It is also looking certain that this year will finish in either 3rd or 4th position overall as it seems both 2022 and 2023 are just out of reach now with so few days left to change very much.

What is also significant is how once 2024 is set into history on the CET means this pushes the only year pre 1990 off the bottom of the top 10 warmest meaning that the top 10 will from next year only contain years from 1990 onwards.

The new top 10 would contain

7 years since 2010 - 2022, 2023, 2024, 2014, 2020, 2011, 2018
1 year between 2000 and 2009 - 2006
2 years between 1990 and 1999 - 1990 and 1999

When looking at that apart from what seems to be the outlier 2011 which was a strange year to come back with such a warm mean the rest of the years are all post 2013 which seemed to mark a big turning point for warmth with 2022 the next big step upwards as even this year is going to be very close to 11C if we don't quite achieve it in the end.

[Metwatch]

Calculating the annual mean based on all the months' CET which I think is as accurate as doing all the daily values, for this year to see a 11C CET, December would have to finish 7.4C which is now impossible.

A 6.8C or 6.9C finish for December is most likely, meaning the annual CET should end at 10.95C / 10.96C? That would be identical to 2006.

[Sceptilli0naire]

On 26/12/2024 at 18:27, SqueakheartLW said:

What is also significant is how once 2024 is set into history on the CET means this pushes the only year pre 1990 off the bottom of the top 10 warmest meaning that the top 10 will from next year only contain years from 1990 onwards.

The new top 10 would contain

7 years since 2010 - 2022, 2023, 2024, 2014, 2020, 2011, 2018
1 year between 2000 and 2009 - 2006
2 years between 1990 and 1999 - 1990 and 1999

And as 2025 will almost certainly be a top 10-er as well as global temps are staying as high as they have been (the correlation isn't perfect but the last few years being the warmest ever globally seems to have translated quite nicely), and as I don't see another 2021 happening in the near future, it will probably be only two more years until the list only contains years from 2006 onwards.

Mad times we live in.

It makes you wonder what's in store for us. Before 2000, 10°C was rare. By 2015 10°C had become the norm, and now in soon-to-be 2025, 11°C is becoming the norm. It's actually a really good reflection of the long-term global warming.

As for 2011 being an apparent outlier, it's easy to think it wasn't a very warm year, but keep in mind that it was only the three summer months that weren't above average, and after them, only January and May weren't significantly above average. February 2011 was very mild, March was quite warm, April obviously the hottest on record, September and October both very warm, November exceptionally warm and December also very warm.

When it comes to annual records, really it's only the shoulder seasons, and somewhat the winter that matter. 2022 was a rare exception where the summer really pulled. Spring was above average but nothing special and tbf there was a total lack of winter over 2021/22 but January wasn't particularly mild. October 2022 was one of the warmest on record however December was below 61-90 averages so the hot summer definitely pitched in on the record. Almost all the other record years had the shoulder seasons as the most exceptional. 2006 had July ofc but the autumn was also very warm with September the joint-warmest on record. You might think 1990's summer got it the record but this wouldn't be accurate. August was the highlight yes but 89/90 was almost as mild as 88/89 and spring was also very warm. July wasn't anything special and June was outright below 61-90 averages iirc. I can't imagine autumn 1990 was particularly below average although I don't know how it actually played out.

This year might actually be the best example of this, we had no discernable winter this year (not until November anyway), February was the mildest on record along with 1998 and spring was the mildest on record. Summer was bang on 91-20 average for the CET region I'd think and then autumn was very average. Then December has again been quite mild. So the summer wasn't even remotely involved in 2024's warmth.

48 minutes ago, Metwatch said:

A 6.8C or 6.9C finish for December is most likely, meaning the annual CET should end at 10.95C / 10.96C? That would be identical to 2006.

Correct me if I'm wrong but this would make 2024 the joint-fifth warmest year? As 2011 was the warmest on record at the time iirc, unless that was nationwide and not just the CET. Otherwise it'd be joint-fourth behind 2014, 2023 and 2022.

[The PIT]

Sunny Sheffield looks to be 6.9C +2.5C above normal and the year 10.7C 4th warmest. Looked certain to smash records until we got to summer.

[LetItSnow]

29 minutes ago, Sceptilli0naire said:

2022 was a rare exception where the summer really pulled. Spring was above average but nothing specia

Not really true. Spring 2022 is the 7th warmest on record and would be warmer than all springs before the 21st century except 1893. 2022 is a rare case where almost the entire year contributed to the anomaly. Shame January 2023 and December 2022 couldn't have flipped places to make 2022 stand out even more. Deserves the accolade of extreme warmth more than 2023 and 2024.

Edited December 31, 2024 by LetItSnow

[Sceptilli0naire]

 The PIT A bit like 2007; was smashing records until it dropped everything right around May or June and didn't get the record anomalies back until winter (07/08 was one of the warmest on record iirc).

 LetItSnow Huh you're right, I underestimated how warm spring actually was. Shows you where we are that 2022 didn't feel like a particularly warm spring.

Makes you wonder what next year will bring. I've heard the xxx5s are notorious for crazy weather (and the last one had some major craziness for sure) so we'll see what happens. With global temps as high as they are there's bound to be something exceptional.

[LetItSnow]

 Sceptilli0naire It is funny but for whatever reason the 5s usually bring all the stops out with a tendency for extremes. Maybe a year with more notable cold than we've been used to, but some notable heat at the same time.  Been going for an amplified seasons type of year myself, bit like 2003. If that is the case then it would probably be a lower CET year than recent.

[Sceptilli0naire]

 LetItSnow If anything it's probably more likely that we'll just see a lot of heat extremes next year. I can't see anything notably cold happening anytime soon although of course a period of single-digit highs and freezing nights is colder than usual these days.

[North-Easterly Blast]

 Sceptilli0naire I would not say that an annual CET above 10*C was rare before 2000 - I would say that it was rare more like before 1988 / 1989.  Between 1989 and 2000, only 1991, 1992, 1993 and 1996 were below 10*C for the annual CET.

2022 certainly proved to be another major time period ushering a warmer era still, with an annual CET above 11*C for the first time, and 2023 also was as well.  I think that it now looks unlikely that 2024 will turn out to be an 11*C+ year, but it still could be close.

[LetItSnow]

 North-Easterly Blast It's strange to me to think that when 1989 had an annual C.E.T of 10.5 that it would have been considered remarkably warm. All but 4 years of my life have been over 10C! Meanwhile before 1989 there were only 12 years above 10C and only 3 of them were at/above 10.4C. How you feel about a 10C year will be how I feel about an 11C year. Now we wait for the first 12C year...

 Sceptilli0naire To be fair I meant notable for our time, not neccesarily historically notable. You never know though!

 

[LetItSnow]

Looks as though 2024 is in at 10.96C. Just failed to scrape a third year at 11C, but only just. Slides into fourth place as 2006 is at 10.95C. 
 

We can say now we are in an unprecedented state in the modern recording era. We will now see if this has been spurred on by extra global heat due to varying factors or whether this is the next “step”. A poster years ago spoke about stages in the changes with 2006-7 being the stage 4 aka unprecedented levels before we generally went back to stage 3 during most of the 2010s (and a blip back into stage 1-2 in the late ‘00s/‘10s). Will this end up being a final push into stage 4 or just a blip and we’ll go back to 2010s levels in the next few years? We will see. Scary but fascinating times. 

[Cloud2]

The 12 month rolling CET is down to 10.61C, which is the lowest it has been since March 2022, and with last years record warm spring coming up it is bound to end up lower in the near future.

[WYorksWeather]

 Cloud2 Yeah it would take a very warm March to match last year which looks less likely with the SSW, and April was on the warm side and May very warm (not really feeling it of course with how wet last spring was). Rolling mean could well drop another 0.2C even if the spring is just closer to modern norms rather than being cold.

The next opportunity to really increase the rolling mean will be June-November, which was relatively unremarkable last year.

 

 

[Finleyboy0]

What is the 12 month rolling CET at right now? and can someone send the link to it pls

[Cloud2]

 Finleyboy0 The 12 month rolling CET is currently at 10.59C

[Finleyboy0]

 Cloud2 Can u send the link to it so i can look at it myself pls

[WYorksWeather]

 Finleyboy0 Managed to find it on Starlings Roost Weather.

Starlings Roost Weather

STARLINGSROOST.DDNS.NET

[Cloud2]

After another extremely warm Spring the 12 month rolling CET is currently at 10.63C

[WYorksWeather]

If the current annual anomaly sustained to the end of the year we'd be in for another 11C annual CET. Still a long way off though of course.

[BlueSkies_do_I_see]

We now only need to avg 1.57C above the 1961-1990 mean to beat the record annual mean CET of 11.18C

Since Jan 2023 the average mean monthly CET anomaly is 1.65 °C, so if recent warming trends continue it will be close.

Edited June 30 by BlueSkies_do_I_see

[WYorksWeather]

 BlueSkies_do_I_see Should be noted though this is only around the fifth warmest first half of the year - quite a lot of years started as warm as this but fell back a bit in the second half. Makes sense since there's often an element of reversion to the mean over the full year.

I think we will have a better idea of the likelihood of an 11C and/or record-breaking year once the summer is over. If it's a very hot one it becomes quite likely since colder than average months have become such a rarity, but if the rest of the summer is more moderate it's probably less likely we head towards a record or an 11C year.

[BlueSkies_do_I_see]

 WYorksWeather I just added a bar chart just as you commented 

 

2024 started really strongly but had a disappointing June. Can you see 2025 falling away? I personally think July is going to be pretty warm. Hopefully August too!

Autumns and Dec have recently been mild too..

Let's put it this way. If you could only lay a bet  on a 10.9C annual CET or a 11.2C  which would you choose? Equal odds. I would go with the higher value 

Edited June 30 by BlueSkies_do_I_see

[WYorksWeather]

 BlueSkies_do_I_see I'd probably put the over/under at around 11C, at the moment. So if it were whichever is closest I'd go for 10.9C, but I don't expect that low. I'd probably favour another 11C year by about 60/40 but would probably put beating 2022 at more like 35/65.

It does obviously have the potential to change rapidly, if the remainder of the summer is very hot it obviously raises the chance quite a lot, with half the year to go there's more scope for the very warm first half to be cancelled out a bit than once we get to the end of the summer and there's only four months left.

 

[LetItSnow]

A below average January is a distant memory now.