The daily Central England Temperature series is running a little hot at the moment. As of the 18th, this February is currently the warmest back to 1772 with an anomaly of +4.64°C, this meteorological winter [DJFDJFMeteorological Winter comprising the months of December, January & February 2023-24] is the 5th warmest to date with an anomaly of +2.61°C, and this year is the 9th warmest with an anomaly of +2.5°C all with respect to the 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. There’s a good chance that February will be the warmest on record possibly since 1659 when the series started, the winter record looks unlikely to be broken, but who knows about 2024 which is already off to a flying start.
The mean temperature in 2023 just quite couldn’t overtake 2022 as the warmest year on record. Still the mean anomaly since pre-industrial times, which I calculate using a 1772-1850 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO. baseline, is just a smidgeon under +2°C and warming at a rate of 0.18°C/decade.
After unprecedented warm spells at both the start of September and October, Autumn 2023 was always going to end up being one of the warmest on record, and for along time it was, but the single cold spell at the end of November prevented this happening, and it ended up the third warmest since 1659, behind 2006 and 2011 with a mean temperature of 12.2°C, which was 1.4°C above 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO..
The 12th mildest October since 1878. Mean temperature 12.1°C and +1.3°C above the 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO..
The mean of 17.0°C was fractionally higher than that of September 2006. The CETCETCentral England Temperature value wasn’t held back by lower temperatures across Scotland as was the gridded data series.
It’s slightly difficult to gauge the number of heatwaves in Central England. One of the reasons for that is the CETCETCentral England Temperature series is made up of a composite temperature from three separate sites, the other is that the series extend back so far, 1878 in this case, that choosing a fixed value for the whole of the last 145 years is problematic because of increases due to global warming. My DCET application allows the user to define which threshold to use and it’s length. In the example above the application displays all heatwaves of three consecutive days or longer, with maximum daily temperatures of 25°C or higher. The UKMOUKMOThe Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy current criteria for heatwaves is 25°C for a large part of the UKUKThe United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland.. Of the three sites that are used to calculate a composite temperature for central England at the moment, one of them Stonyhurst is in the 25°C region, the main one Rothamsted, is in the 28°C region, and the other Pershore, is in the 27°C region. So you could argue I should use the weighted average of the three 27°C but what the hell. The longest heatwave in Central England lasted for 16 days, from the 23rd of June to the 8th of July 1976. That’s one day longer than the 15 days of 2018 for similar dates. The earliest heatwave in the series back to 1878 if I’ve done my programming correctly was from the three days from the 28th to the 30th of May 1944. The latest heatwave was the three days that started on the 29th of September and lasted to the 1st of October 2011. I’ve catalogued 145 individual heatwaves in 145 years which is a bit of a coincidence and not a lot of people know that. The recent record breaking heatwave for September (2023) that’s just finished (and here I’m assuming it finished on the 10th) lasted for seven days from the 4th to the 10th of September, which makes it the joint fifth longest heatwave in the series to date, in fact it equals the seven day heatwave that occurred earlier in the year in June.
Are heatwaves getting more common?
Yes, of course heatwaves are getting more common, CET temperatures have been rising at the rate of 0.254°C per decade for the last 50 years, so they are bound to get more frequent and longer lasting. The chart below gives you an idea of the increase, it displays a bar chart of the annual number of days when daily maximum CET exceeds 25°C. I have added a 10 year centred average to the chart, and also a linear trend from 1878 to 2023. A shorter trend would show a much larger rise than the 0.4 days/decade increase than this trend shows but I am starting to flag and it’s getting near to dinner.
The summer [JJAJJAMeteorological Summer comprising the months June, July & August] consisted of the fifth warmest (mean anomaly +2.4°C) June in central England, followed by the two non-descript months of July (mean anomaly -0.7°C) and August (mean anomaly -0.2°C). You’ll notice that there were no warm spells to speak of after the 25th of June, when the summer switched to average mode. The June 10th to the 16th was a quite remarkable spell, setting 7 consecutive new maximum daily temperatures for June. The rest of the summer also set five new high daily minimum records and one for the lowest minimum on the 26th of July (8.6°C).
Daily CETCETCentral England Temperature | 1 January 1772 – 25 August 2023 | 365 day moving average
This year might have seen the warmest month in global temperatures, but the warmest 365 days in the CET series still belongs to the 11.71°C which ended on the 2nd May 2007. The graph shows all the daily mean central England temperatures for each year since 1772, with 2022 in blue, 2023 in red and 2007 in black. Up until the middle of February, 2023 was out on top as the warmest in the series, but since then the average for 2023 has very slowly cooled, at the same time back in 2007 the 365 day average was still warming. At this juncture, by that I mean the 25th of August, 2022 is now the warmest 365 days but with a mean temperature still much lower than the record 11.71°C set in 2007. If this graph of multiple line series for each year since 1772 looks a little bit complicated, it is, so study it a moment, and I’m sure everything will become clear😉
The daily mean CETCETCentral England Temperature so far for this year (8 July) has finally caught up with last years, the warmest year on record in central England, but at this point 2023 is still only the 6th warmest, and both 2022 and 2023 both trail 2007. It’s noticeable that it was at this time last year that the mean temperatures accelerated, no doubt with the help of the hottest day in the series.
I resurrected from the archives, and reworked one of my old viewers in my Daily CETCETCentral England Temperature application this morning. It can show means, anomalies, extremes, deciles, quintiles and centiles of weekly temperature since 1772 in a heat map style data grid. It looks like I’ve just commenced the 3,606th week of my life, and that image shows all of them.
It may have been the warmest June in the HadUK gridded data set, but it’s only fifth warmest in central England going right back to 1659. The other unusual thing is that a linear trend in June’s from 1659 to 2023 shows no warming during that time.
The mean temperature in January 2023 was 5.2°C in central England which was 1.4°C above the 1659-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. 18 of the 24 January’s this century have been warmer than average. The cold spell in the third week wasn’t able to make up for the very mild first half of the month.
Just as I found in the gridded UK data series from the UKMOUKMOThe Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy that 2022 wasn’t the warmest 12 months on record, I also find that it isn’t the warmest 365 day period in the CETCETCentral England Temperature series either. That accolade belongs to the 365 days between the third of May 2006 and the second of May 2007, with a mean temperature of 11.71°C which is far higher than the 11.15°C temperature for the year 2022 in central England. It may not mean much to most people, but I think it makes a bit of a mockery of all the hoo-ha that we’ve had to endure recently from the media about 2022 being the warmest year, when in reality it occurred almost 15 years earlier both in the CET series and the gridded series.
Dear Diary, 2022 was the warmest year in Central England in a monthly series that started back in 1659, the mean of 11.1°C was +1.7°C above the 1659-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. It’s been on the cards for many months now that 2022 would be the warmest, and thankfully now that it’s finally been confirmed, we can move on to the next extreme. Seriously though Central England is warming at an incredible rate at the moment, the 50 year linear trend is running at +0.258°C per decade, and if it keeps going on like this people will begin to talk.
Dear Diary Believe it, or believe it not diary, the recent cold spell that has just come to an end was the joint sixth longest cold spell since 1772 in Central England. The Gannt chart lists all cold spells that lasted at least 10 days, with daily mean anomalies of -4.9°C or lower. The table on the left lists all cold spells ranked using the dense ranking method. That’s based on anomalies calculated against the 1878-2021 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. It’s no wonder the Daily Mail was getting hot under the collar about the Met OfficeUKMOThe Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy’s response to it and I think it’s longevity caught many people out. Cold spells of that length are not that common, it might not have been as severe as some in the past, but it lasted ten days from the 8th to the 17th of December.
Dear Diary After a fiddly bit morning of programming, I can finally reveal that 2022 WILL be the warmest in the Central England daily series which started in 1772. That of course assumes that the rest of the month, from the 11th onward, has anomalies no higher than -3.5°C for each of the next 21 days. That’s not impossible of course, but even after a cold start such as we’ve seen this December, the mean temperature for the first ten days is still only 2.37°C below the December LTALTALong Term Average. This is usually defined as a 30 year period by the WMO., which would mean that the very low anomalies of the last few days would have to continue for the rest of the month. If this finding is true for Central England, I think it’s more than likely it’ll be true of the gridded data for the whole UKUKThe United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. as well. I found it easier to write that small program than to sit down and work it out with pen, paper and calculator, which must say something about how my brain works.
Dear Diary, Unsurprisingly, Autumn 2022 [SONSONMeteorological Autumn - September, October and November] ended up the third warmest since 1659 in Central England, with a mean temperature of 12.4°C, which was +2.4°C above the 1659-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. There were only a few colder than average spells with warm spells dominating for long periods.
Dear Diary, November 2022 was the joint fifth warmest in Central England since 1659 with a mean temperature of 9.2°C which was 2.8°C higher that the 1659-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. November was the eighteenth month with above average mean temperature in Central England.
With regard to global temperature the IPCCIPCCThe Intergovernmental Panel on Climate Change is an intergovernmental body of the United Nations responsible for advancing knowledge on human-induced climate change.
It was established in 1988 by the World Meteorological Organization and the United Nations Environment Programme, and later endorsed by United Nations General Assembly. uses the reference period 1850 to 1900 to represent pre-industrial temperature to measure the degree of global warming that has occurred. They say about this reference period in their 2018 report:-
In principle, ‘pre-industrial levels’ could refer to any period of time before the start of the industrial revolution. But the number of direct temperature measurements decreases as we go back in time. Defining a ‘pre-industrial’ reference period is, therefore, a compromise between the reliability of the temperature information and how representative it is of truly pre-industrial conditions. Some pre-industrial periods are cooler than others for purely natural reasons. This could be because of spontaneous climate variability or the response of the climate to natural perturbations, such as volcanic eruptions and variations in the sun’s activity. This IPCC Special Report on Global Warming of 1.5°C uses the reference period 1850–1900 to represent pre-industrial temperature. This is the earliest period with near-global observations and is the reference period used as an approximation of pre-industrial temperatures in the IPCC Fifth Assessment Report.
I thought I would look and see how the CETCETCentral England Temperature series was doing and see if it was getting close to the magic +1.5°C. The daily mean maximum and minimum only began in 1878 so it’s not possible to calculate mean values using this data, but daily mean temperatures are available back to 1772, and so it’s possible to calculate a mean for 1850-1900. It’s also possible to go back further and calculate a mean from 1772-1900, or better still calculate a mean for the period 1772-1850, which in my opinion is a better start for the dawn of the industrial era or the industrial revolution.
The anomalies in the bar chart are larger than you would normally see because I’ve based them on a long-term average for the period 1851-2000. Annual mean anomalies nearly exceeded 1.5°C back n 1949, and in recent years the 1.5°C barrier has been breached at least six times including this year (2022) which looks likely to become the warmest year on record. So we’ve not quite reached the +1.5°C mark globally but we are not far off in central England. I wonder what Gordon Manley would make of it all?
What caused the cooling between 1950 and 1980 in global as well as temperatures in central England? Maybe it was the airborne testing of thermonuclear weapons that followed the second world war and which continued till around 1976 according to Wikipedia. Natural variability or man made? My money’s on the latter in this case.
The year 2022 is still currently the warmest year in the CETCETCentral England Temperature series that started back in 1659. I make the mean temperature up to the 13th of November 12.08°C a massive +1.97°C above the 1961-1990 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO.. It’s closest rival is the year 2014 with a mean of 11.72°C. I can’t see 2022 being beaten now, the only thing that might stop it is if we get a repeat performance of December 2010, which to be honest looks highly unlikely.
I can count at least twelve new daily maximums that have occurred this year (red diamonds), and another seven new daily high minimums as well. If you like me like snowy winters this graph does make pretty bleak viewing, with few in the way of air frosts.
