Little Rissington WMO03647 – Another example of why simply playing with numbers does not work.

51.86063 -1.69287 Elevation 210 Metres amsl. Met Office CIMO Assessed Class 1. Installed 1/1/1942

RAF Little Rissington weather station is currently assessed by the Met Office as a fully reliable premium quality weather station. In this review I will confirm that assessment is correct and it definitely is a good site. I will also demonstrate why its data is unsuitable for inclusion in the historic national record and why Met Office numbers cannot be taken at face value. This is a cautionary tale for anyone assuming that numbers can simply be input into a computer programme and graphics produced to prove a point – they (more often than not) simply cannot.

Firstly the 100 metre radius CIMO exclusion area prohibits “A source of heat (or expanse of water)” from occupying more than 10% of the area. Although there are roadways, these just (only just) come in under that parameter as shown below. The site is flat and ground cover, though perhaps over neatly manicured like nearly all military sites, is as “natural” as necessary to meet requirements.

All 21st century Google aerial images indicate a perfectly acceptable site so why my suggestion that this site cannot be used historically? Although the archive suggests a continuous record from 1942, the reality is far from that.

Typical of aviation sites, the Stevenson screens are often relocated for operational reasons. Unfortunately Met Office records tend not to openly show that and it usually requires deep digging into the files to ascertain where things really were. For example, all the digital records going back to 1957 show the current site coordinates but are they trust worthy? No they very rarely are, so it comes down to viewing original manuscript. Below is the 1957 first digital record showing the current site – also note elevation of 210 metres..

The next interesting indicator is that reference is made to two separate District County Network Numbers (DCNN) as here:

Note that DCNN 4994 stops 30/4/1976. DCNN 4995 seems to run simultaneously for a while before taking over. The Met Office specifically states that –

” Over time certain instruments, or the whole enclosure, may be relocated some distance away from the original site. Where the distance moved is small, the observations obtained from the new site may have exactly the same climatological characteristics as previously and it makes sense to regard them as coming from the same source or station distinguished by certain identifiers. Where the distance moved is large, or, where the exposure at the new site is sufficiently different that a detectable impact on the measured climatology is judged likely, it is appropriate that observations from the new site are labelled by a different set of identifiers.”

Clearly the move was over a long distance and different climatology as indicated on the original manuscripts. The manuscript coordinates are not accurate enough to exactly pinpoint the original site but a small note in the “remarks” section gives corroboration. “

2000-02-09

Current

SITE INFORMATION

OLD SITE WAS AT GRID REF 4209E 2191N ELEVATION 226M UNTIL 1976

Viewing the map now indicates a removal distance of over a kilometre, a 16 metre higher elevation, alongside another of those large settlement tanks featured at Cranwell and very close to buildings and the main parking apron.

Further to this major relocation is added a surprising lack of any actual readings at all from 30/4/1976 to 1/1/1992 – an almost 14 year unexplained gap as hidden deep in the archives.

Now look at how the Met Office gets away with displaying the data to the general public, researchers, students and those responsible for education in the UK. No mention of relocation nor the original poor standard of the site and the massive gap in actual readings. In the example screen shot below there were no readings for 14 of the 30 years and those that exist were from 2 different locations.

The points I am making here are those that I tried to convey in my Tom Nelson podcast. It is remarkably easy to manipulate numbers using effectively covert (alleged peer reviewed) processes but any such exercise is pointless if the original numbers have no genuine validity. The Met Office seems to feel exempt from such a duty of care as I believe I am continuously demonstrating in these posts. Accuracy and integrity seem only to be enforced on those, like me and many others, perversely forced into supplying “disproof” of the supposedly credible authority. Little Rissington clearly demonstrates not only the unreliability of much of their information but also the complete fabrication of much of it.

The current Little Rissington site is good but only possibly/probably from 1992 onwards – so obscure are Met Office details I cannot guarantee the date from which this site commenced. This is also a cautionary tale for any others seeking to simply “reinterpret” Met Office data – its veracity has to be positively confirmed first.

Source: https://tallbloke.wordpress.com/2025/04/16/little-rissington-wmo03647-another-example-of-why-simply-playing-with-numbers-does-not-work/