WYE Addendum – a detailed look at what the actual data tells us.

I recently reviewed the now closed but historic weather station at Wye Agricultural College in Kent. All the evidence showed this site to be in a very good location. This location had not changed throughout its long history and the site had been very well maintained in its operational life. Its observations record was excellent with very, very rarely a missed day. Perhaps equally importantly there had been no instrument type changes over its lifetime. This deserved detailed analysis as such a quality site would represent a large inland area of the county of Kent. Here are the initial findings.

Firstly I am deeply indebted to former professional auditor Dave Woolcock for his extensive and diligent work on this. Dave has downloaded from the official CEDA files all the detailed temperature records for EVERY weather station (open and closed) that exists on their database. He compiled both running maximum and minimum temperature averages from the archived 17,210 days ( i.e. 34,420 readings) available. His full methodology (in his own inimitable straight forward style) is included at the end of this post but his basic precis is:

“Dead short version. Read and combine the CEDA csv file data into a sorted XL file (the data is all DLY3208 so one day per row). Compute 12-month moving average for tmin and tmax using @Average of the previous 365 days. Plot using XL charts”

{DLY 3208 is the daily logging system used by the Met Office. Manual stations supply one timed set of readings per day at 09:00 GMT}

Average Maximum.

Average Minimum

I would like to re-emphasize this is not a cherry pick. Wye simply represents the first long term operational site that I could establish meeting the following criteria:

1. CIMO Class 1 or 2 Site.
2. Not relocated over data reporting period.
3. Identified good maintenance with no significant change of surrounding conditions.
4. Not subject to significant Urban Heat Island effects.
5. No instrumentation changes (i.e. from LIGT to PRT)
6. Consistent good quality observations record. (WYE was excellent)

I leave it to readers to draw their own conclusions from the above representation.

I stress that all this data comes solely from the MET Office themselves and is readily verifiable from the CEDA link given above. Photocopied manual records from 1924 to 1958 exist for this site (in Fahrenheit) on the Met Office files here.

https://digital.nmla.metoffice.gov.uk/SO_13c674e7-a2fc-4263-9283-e76a1c8ccc63/

I will transcribe these myself in order to reconstruct the preceding 34 years in due course though this will be a somewhat laborious process.

I would very much appreciate as many readers views and comments as possible on this (good or bad) to assist moving the Surface Stations Project beyond just the weather station site review phase and into a new national historic temperature reconstruction.

And now for the important bit: Courtesy of the much appreciated Dave Woolcock.

——————————————————————————————————————-

METHODOLOGY

1. Scoop data for Wye from CEDA csv files and accumulate into a single XL sheet sorted into date order

2. Highlight all the data in the tmax column and Insert / Chart (line graph)

3. Pick light orange colour, set line width to .25pts, change the x-axis labels to pick up the date column and move Labels to “low” position.

4. Add a MA column (H) by scrolling down a year and averaging the first year.  Copy down to the end. Do same for tmin in column I by copying the formula across and down.

5. Return to graph and add in another data range – column H

6 twiddle colours and line width to look good, add in chart title. Save to PNG file. 

7 copy / duplicate the entire chart below and edit it. Change data ranges to point to tmin and the tmin moving average. Change colours to cool blue. Save chart to PNG file.

8 the data is “as is” not adjusted for throwback so for each given day tmax and tmin will be out of sync compared to true MO practice. But for this exercise it doesn’t matter. If it did we could just shift tmin down a row.  If the data were based on 12-hour readings we would need a lot more data prep before we could plot it.

Source: https://tallbloke.wordpress.com/2025/08/14/wye-addendum-a-detailed-look-at-what-the-actual-data-tells-us/