I’ve added another viewer, to the ever expanding list of viewers that I’ve developed over the years, to the application I use to visualise data from the daily Central England Temperature series. This one finds all the daily extreme warmest and coldest daily temperatures, highest maximum, lowest minimum, the highest minimum and the lowest maximum etc etc. As you can see in the screenshot above it consists of three data grids with a matrix of months and days to display the year the extreme occurred (left-hand grid), along with the actual value (centre grid), and the resulting anomaly (right-hand grid). In the above example I’ve highlighted in yellow any records that occurred in this decade (2020-2024) which is quite remarkable as they are still a full five years to go before it ends.
I’ve also added functionality to generate a simple animated GIF of the results in a single image.
I’ve redesigned how I visualise moving averages in my Daily CETCETCentral England Temperature program to generate a user definable moving average graph of daily CET values since 1772, this ended up being something of a job because now I dynamically plot over 250 annual ‘silver’ coloured line series, one for each year, as a backdrop. Over this backdrop I plot a 30 day moving mean for the year (dashed black), along with its corresponding +1/-1 standard deviations (dashed red and blue lines). On top of that I plot the coldest (bold blue) and the warmest (bold red) 30 day period ending 13th of April. Finally, I plot the 30 day moving average for the last 365 days (bold black with yellow outline), and at the same time I list the latest values in a ranked table on the left. With it, I make the latest 30 day mean temperature 10.57°C for the 13th of April, that’s the warmest 30 day period for that date in the series since 1772, and 3.53°C above the LTALTALong Term Average. This is usually defined as a 30 year period by the WMO. for 1772-2023. As you can see n the graph and the table this is significantly higher that the previous warmest of 9.79°C in 2017. Hopefully all this new code is producing accurate results 😉
Not surprisingly, in this ever warming world of ours, the dates of the earliest and latest air frosts in Central England getting respectively later and earlier. The code behind that produced the scatter graphs below was a lot harder than I imagined. Along with the scatter graph and data grid, I also decided to add a smaller horizontal bar chart just to plot the annual distribution. The application is a lot more versatile than just finding the earliest and latest frosts and will come in useful in spotting other events in the daily CETCETCentral England Temperature series. As you can see from the linear trend in the graph below of minimum temperatures, the date of the latest air frostair frostAn air frost occurs when the temperature of the air falls below 0.0°C in Central England is now closer to the 5th of April, much earlier than the 16th it was back in 1878.
The date of the first air frost is now 11 days later on the 13th of November, rather than the 2nd of November, as it was closer to back in 1878.
I estimate the first day of spring in Central England this year occurred on the 8th of February, that’s 42 days earlier than the accepted date for Spring of around March 21st depending on the exact date and time of the vernal equinox. That made it the joint seventh earliest spring in the CETCETCentral England Temperature record back to 1772. I use the average number of degree days from 1773 to 1802 to calculate a baseline to estimate the date with. Not a brilliant method. let me know if you can think of a better one. The last late spring, and the only one to occur in this century was in 2010. The linear trend reveals that springs are now arriving 24 days earlier than they did in 1772. Apologies for the late arrival of this story 😉
Winter 2023-24 in Central England was a mild affair with only two main cold spells to speak of. One in the first week of December to start, and another in the second and into the third week of January. I made the mean temperature 6.5°C which was +1.68°C above the 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO. making it the fourth mildest winter since 1659, behind the winters of 1868-69, 2015-16, and 1833-34. Despite this three new record low temperatures occurred, along with nine new record maxima and eight new record high minimum temperatures.
The mean temperature for February 2024 in Central England as far as I can make out was 7.77°C. That wasn’t just quite high enough to beat the mean of 7.9°C in 1779 into second place, but was still a very mild +2.8°C above the 1991-2020 LTALTALong Term Average. This is usually defined as a 30 year period by the WMO. for the month.
I reworked an old application last week that I use to generate a simple six hourly North Atlantic Oscillation from NCEPNCEPThe United States National Centers for Environmental Prediction (NCEP) delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities. reanalysis data that I download. It’s simple, nothing complicated using geopotential heights at 500 hPahPaA Hectopascal is the SI unit of pressure and identical to the Millibar or anything like that, just the pressure difference between 65N 25W and 37.5N 25W. A well as plotting the NAONAOThe North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in the strength of the Icelandic Low and the Azores High, it controls the strength and direction of westerly winds and location of storm tracks across the North Atlantic. I also add charts of the daily mean anomaly from the CETCETCentral England Temperature series, along with the England Wales rainfall from the daily UKPUKPUKP is a gridded datasets of UK regional precipitation. series, both of which I download 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. As you can see in winter at least there is a strong correlation between the NAO and CET & UKP. I’ll add more viewers to examine the correlation, so much to do, and so little time, as the Joker said.
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.
