Cardiff:Bute Park – A long and detailed report with some incriminating remarks from the Met Office – Plus a sting in the tail!

The above image was taken in 1978 shortly after the installation of the weather station in the horticultural working area of Bute Park. It is in the same location to this day but the surroundings have changed out of all recognition to such an extent that this site is now meteorological junk and in, fact, has been so for a very long time. Unfortunately it has taken an equally long time for the Met office to figure that out despite multiple inspections. This report includes examples of crass elementary mistakes and a clear refusal to see the obvious. Despite this obvious evidence it is also a demonstration of ridiculous expenditure and investigation presumably to be seen to be doing something and covering one’s back together with several contrived admissions. A long and detailed report with that sting in the tale/tail I mentioned a few posts back.

An analogy with meteorological relevance…..that will become evident later.

The calculation of the theoretical maximum power output of a flow turbine ( “P” measured in Watts) is based on three variable factors, density of flow medium, area and volume. Using a horizontal axis wind turbine (the common type visible onshore and offshore) as an example, the basic formula is based on:

Air density (ρ) in Kilograms per metre cube – linearly variable with air pressure in the range of approximately 1.15kg/m3 to 1.25kg/m3.

Swept Area of the Blades. Measurement derived from the circle described by the rotor blade tips in square metres thus operates to the conventional formula of πr² i.e. Pi (3.14159) multiplied by the radius squared. {n.b this is Key Stage 3 mathematics.}

Wind velocity (V) measured in metres per second (m/s)

This becomes Pₘₐₓ = ½ × ρ × πr² × V³ There is, however, a caveat that if all of the available power were “extracted” from the movement of the wind then the air on the far side of the turbine would be static and thus block any further air passing through. This restriction is defined by Betz Law and the maximum power available is 16/27ths (approx 59.3%) of the theoretical figure.

The main points to note are that whilst the air density is minimally variable the other factors operate to a square law and a cube law. This means that “size and speed” magnify each other dramtically. 1980’s style turbines were typically in lower wind speeds (primariy onshore) with small rotor blades (5m to 12m blade length) whilst their modern counterparts in the UK are now predominently offshore with higher winds and up to 75m blade lengths.

Wind turbines start operating when wind speed is sufficient to consistently overcome static inertia – a “cut in speed” of around 4 m/s (14kph/8.5mph) . They can then operate up to around wind speeds of 25m/s (90kph/56mph) with progressively precautionary adjustments (feathering) beyond which they are braked for their own security.

The range of theoretical output from these variables is impressive. A 75 metre blade is 15 times the radius of a 5 m one thus the swept area is 15 squared = 225 times greater. Equally dramatic is wind velocity varying from “cut in” at 4m/s to say 24m/s being a factor of 6 fold which is then cubed = 216 times. These numbers are multiplied making that 75 metre bladed turbine in high wind versus a small turbine at cut in speed equate to a difference of 48,600 fold. In operational reality wind turbines are optimised to operate at consistent “rated” wind speeds of between 11 to 13 m/s and the magnitude of difference is considerably different to the above theoretical but is, nevertheless, still extremely large.

Given that air pressure and wind are meteorological variables, it is imperative for the Met Office to supply accurate forecasting of them for the benefit not just of the wind turbine operators and the entire electricity generation industry, but also the general public whose lives are so dependent on that supply. Accuracy is crtically important.

Relevence of this analogy.

“Climate Science” in relation to recorded weather changes (particularly temperature) over hisotric time often appears to operate outside of regulated and accurate scientific rigour. “Data” however spuriously obtained seems to be all that matters once tortured though computer models to derive the desired end result. The provenance of the numbers (scientific accuracy) used as inputs is often unknown to those engaged at the keyboard end, indeed many do not have any significant meteorological training or qualifications at all. I will not name individuals out of courtesy but many involved in the Met Office /CRU can be seen to be qualified in non meteorological specialisms such as mathematics or computer sciences. Whether or not their “building blocks” of observations numbers are meaningful is likely not known to them to the extent that the recent data from almost derelict sites such as Eastbourne carries the same weight as those from Class 1 Rothamsted. The “system” accepts the selected numbers and the predetermined grid structure populates the entire system in the ultimate black box machinery that cannot transparently advise of the original inputs as they are not retained “outputs” of the process. A bizarre situation.

Now compare this climate science approach to that required of, for example, offshore wind turbine construction companies.
They most certainly cannot use “near enough for Jazz” calculations as there are serious implications if they get it wrong. Doctors are said to bury their individual mistakes whilst engineers have been held responsible for mass graves. Indeed meteorologists (not “climate scientists”) have also been held, and still are, responsible for mistakes. Forecasting is a serious business at which the Met office performs particularly well. It is not just Michael Fish who carried the can back in 1987 for not even getting it particularly wrong.

The problem, for me, is the way the backgtound system at the Met Office has been allowed to deteriorate simultaneous with the ascent of activist style presentation of historic and current data to create an altered scale impression of the very recent climate record. For example the trend lines on the Met office “Time Series” graphs are divined using a triangular-weighted kernel smoothing filter, using 14 years on either side of each target year. The trend point for 2025 uses adjusted “data” from 2011 to 2039 i.e fictitious numbers but at least the process is “peer reviewed”.

Cardiff Bute Park is my “text book” definition of everything that is wrong and has led to this site’s readings (as with lot’s of others) being rendered unusable…….but they still are being used.

Preamble over but the relevence will be shown later in this review.

Cardiff:Bute Park History.

Cardiff Stevenson Screen observation taken in 1978.

The site was established in 1977 in what may not be a Premier League status site but certainly was acceptable and suitable for purpose as far as can be established not only from contemporary imagery but also retained hand drawn site plans below.

There are no indications of the site being relocated but clearly there were major alterations to the surroundings over the intervening years and those buildings in view in the headline image are stll there today. The site first came to the attention of the Talkshop in 2012 when Tim Channon reviewed the site with his typical forensic precision and notably included multiple circled areas of known radii.. Tim had succesfully reviewed every WMO site and was intending to leave the project at that but added a few Climate reporting sites that he felt were especially suspect. The comment from reader “Caz” was very enlightening. {n.b. broken links have been deleted}

“There has been a lot of controversial restoration work carried out in Bute Park of late. The internet is full of protests by various groups and individuals. The work that most affects the Stevenson screen is a new delivery circulation road for the nursery, figure 46 Page 222 in the restoraton pdf to be found in the link below. The Nursery has also become an education center but this work does not seem to include the area that the screen is sited. The conifer hedges on the Southern and Eastern sides of the main area have been cut down to be replaced by walls and climbing roses. The aerial mapping sites have not got this work yet.

The big problem with the site is that the screen is within a walled and hedged garden which is used to create a micro climate for the raising of plants for the park so the readings will not be indicative of the area as a whole. So you would expect the temperatures inside to be more like May than February.

Here is a link to a smaller pdf of a document issued by Cardiff Council to explain their reasoning for the new road and bridge. It does run beside the screen but seems to be over the surface of what is already paved.

I really do think the BBC should give a health warning when they announce that the Welsh capital is warmer than Athens. Walled Gardens are what UK gardeners build to create micro climates similar to Athens.“

From all details apparent 14+ years ago there were problems that had developed with this site. Alarm bells should have been ringing but were not. Note Tim’s link to a BBC article that was authored by Dereck Brockway, a BBC wales weather presenter and former Met Office employee.

Around April 2024 (before I restarted the Surface Station project) the BBC made an episode of their travelogue of Wales called “Weatherman Walking” which aired around October that year. It featured the same Dereck Brockway visiting the Bute Park weather station. By chance I saw this episode and was frankly amazed that two professionals could be openly parading what had become a very poorly sited and exposed screen as if this was just the norm. I featured stills from the episode in my subsequent report expecting the iPlayer link to extinguish after a while. The link did in fact disappear but luckily a second link now records solely the weather station visit section retaining full visuals on the site.

https://www.bbc.co.uk/programmes/p0ht3tdb

Even the starting image above starts to raise big question marks. How are all those green heat absorbant tubs lined up around the perimeter supposed to enhance the quality of the site? Why does it look more like a builder’s yard and car park than a pristine weather station? So many query points – the plastic wrapped pallet by the entrance, surely the production or site staff could at least have made an effort to tidy the place up a bit. Move a few cars out of the way maybe? Lines of more green tubs and the trees (previously not there in 1977) are possibly over 6 metres high almost alongside the enclosure. Surely “Stuart” the manager responsible for all stations in Wales can see all these issues, surely the “Weatherman Walking” is not equally blind to them as well. The new roadway Caz mentioned above is clearly in view and (as will later become apparent) is freely available to park any vehicle at all there.

Perhaps though, most readers have missed the two vastly more important points than all the above problems that simply must be addressed as matters of, no doubt, extreme urgency. What are they? Well in front of the screen is a paving slab (you can just see it?) and on one part of the stand is an electricity junction box! This is the world of Civil Service box ticking.

Remember this quote:

“WMO guidance does, in fact, not preclude use of Class 5 temperature sites – the WMO classification simply informs the data user of the geographical scale of a site’s representativity of the surrounding environment – the smaller the siting class, the higher the representativeness of the measurement for a wide area. Indeed, it should be noted that WMO Class 5 is not the same as a Met Office ‘Unsatisfactory’ inspection assessment, which ultimately determines the ongoing use of a site. We use the Met Office grading system to determine record verification because; it has historical relevance, covering a wide range of long-standing criteria at UK observation sites, the equipment, and the exposure in a holistic manner and has clear meaning to what is acceptable or not. It tells us how much confidence we have in the data and permits comparisons.“

Think about it, Stuart and/or his staff and Dereck visited this site, gave the whole area a good look in a “holistic manner ” and came to the conclusion – “forget the close hard standing, parked vehicles, green tubs surrounding in the sides, the massive sun shading, the total absence of any even slight breeze likely to dare to infiltrate the site and multiple other very damning problems – I know let’s worry about a paving slab and a low voltage/power junction box that most people would not even notice. “

On the above image I have marked both 10 metre and 3 metre “radius” circles. Below are the CIMO regulations for both Class 3 and Class 4. The top of the image is north.

Without even beginning to calculate the extensive area of hardstanding covered in all manner of extraneous heat sources, it is blatantly obvious that the trees and hedges will contravene the stipulated shading angles. This site is unquestionably Class 5 meeting no requirement standards whatsoever.

2.6 Class 5 (additional estimated uncertainty added by siting up to 5 °C)
Site not meeting the requirements of class 4.

This Class 5 rating is exactly what the Met Office assessed the site as shown on both the recent lists I obtained under FOI. Furthermore this site was flagged with an additional “S” rating which I have since been advised indicates “suspect” readings.

With all this background the Met Office still decided to provisionally award the all time highest Welsh June temperature to this site only to, on inspection, have to “redact” this reading.

” In addition, the recent temperature figures reported from Cardiff Bute Park have also been rejected following a detailed review of the site, which found the station no longer meets the standards required for national temperature records.“

The SWAT Report

Following the above announcement at the end of July, a Talkshop reader (I shall call them Alex for anonymity) lodged a Freedom of Information request for the Surface Weather Assesment Team (SWAT) report that ruled out this reading. The response took nearly 3 months but, on receipt, they forwarded me some ( but not all) of the exceptionally extensive response…….. This was an amazing eye opener.

So yes that is what the Met Office has claimed. They had previously confused Diameter with Radius in their caclulation. But then the staggering line

“In effect, this reduces the size of the circle by half and alters the calculation.” {What is “In effect” even meant to mean? ) Apart from being an outright GCSE failure, surely the SWAT team understand the formula I started my preamble with πr² – and that this operates to a square law i.e. doubling the radius causes a fourfold area increment!

How accurate are the rest of their calculations? At how many other sites has diameter been used in lieu of radius? Remember Hastings and the Met office admission that their systems default to Class 1 and “Excellent” unless manually altered? This led to that site and Edenbridge and Cassley being reclassified to class 4. Have the Met Office loaded wrong data into a programme that is serially miscalculating site assessments for areas? Using diameter in lieu of radius reduces the “exclusion zone” to a quarter of what it should be – not a half!

And then there is the, “in effect” admission – this site has not been assessed as Class 4 in recent times but they specifically state it does not meet the implied Class 4 rating they are checking it against.

“This is ouside satisfactory limits for a CIMO Class 4 ( less than 50% within a10metre radius of the screen) and so has been scored CIMO Class 5/Met Office Unsatisfactory“

Okay so what was that about……..”Indeed, it should be noted that WMO Class 5 is not the same as a Met Office ‘Unsatisfactory’ inspection assessment, which ultimately determines the ongoing use of a site”. Yet more weasel words and semantics by the Met Office. Any site that is so bad it had already been assessed “Class 5 S” has been unmitigated junk like this for a very long time and should never have been used for any temperature recording contributing to the historic temperature recording. However, this appalingly bad site is still being used, furthermore just as I have previously noted at several sites such as Floors Castle , even this “record” for June will almost certainly enter the archives. The readings will not be expunged in reality, this station will continue in use largely unchanged.

Below is an example of the reality of this site, the same reality the Stuart and Dereck featured on the BBC.

So is it reasonable to assume from all this that this site is “Excellent” – of course it is!!! The Met Office says so doesn’t it? This is “An Excellent Well Maintained Site” and that’s official. Confused? You should be.

And yet it gets worse still. Despite all this detritus littered around the site, working diesel powered vehicles parking alongside, multiple heat sources, extensive hard standing, sun shading and wind sheltering and just about every possible downside right on its proverbial “doorstep”, the Met Office decided to investigate a potential overnight highest minimum from the same site and day. Clearly expense is no object so call in the services of drone aerial photography. Surely over 75,000 square feet of glass covered area accounts for enough of a “greenhouse effect” when it is under 20 metres from the screen rather than a concert at Glamorgan’s Sophia Gardens Cricket Ground the other side of the River Taff over 10 times that distance away.

Good to know the Met Office is so thorough in exploring every possible heat source – apart from the obvious ones.

In conclusion this all seems to me like absurdity on steroids. Cardiff Bute Park is a very poor site and should not be used to contribute data to the national temperature record. The Met Office opinion of this site is clearly shown to be stageringly incongruous with diametrically opposed views shown of “Excellent” and “Unsatisfactory” in the same reports. How anyone can claim this is a good site and not note on their forms all the problems is surreal. The site is unquestionably Class 5 and has been for a very long time – quite possibly this entire century so far.

The sting in the tale?

There appears to be two differing sets of views on Met Office site quality dependent on whether or not you work for them. Every Met Office screen is Satisfactory, Good or Excellent when their staff are asked despite non employees (like me perhaps) objectively considering many of them junk. In my original report on Cardiff I somewhat facetiously noted the following:

“And of course the screen is in the direct exhaust line of the cars in the adjacent general parking and dumping ground area. Why not simply save all the fuss and bother and just take readings from the car’s thermometers – they would likely be just as (in)accurate.“

My comment was actually a paraphrase of a remark inadvertantly sent to me in 2013 by inclusion in a “round robin” email. I was after professional opinion of the Faversham then all time highest temperature reading of 2003. I quote:

“Being a wee lad of just 12 years old I remember our family car thermometer reading 40C on the A21 south of Flimwell (East Sussex) as we stopped at the Little Chef there…. but I suspect although our car was an official reading, it was probably non-operational ”

The “mentor” of the author of that comment (Jim Bacon – Weatherquest) promptly requested:

“Ray

Just to add, I should have deleted the internal email section of my reply and that is not meant to be forwarded outside of this conversation.”

Pity about that (and other) admissions of questioning the quality of many Met Office sites and records. I doubt if the the author of that somewhat flippant remark (below) would say the same now that he is invested in proving their accuracy.

Source: https://talkshop.blog/2026/11/06/cardiffbute-park-a-long-and-detailed-report-with-some-incriminating-remarks-from-the-met-office-plus-a-sting-in-the-tail/