I noticed recently that the UKMOUKMO The 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 have started to publish and maintain on their website, data files of daily mean maximum and minimum temperatures from the stations that they have used to calculate the composite Central England Temperatures since 1878. I had given up hope of ever seeing this data, which gives a better insight on the machinations the UKMO go through to produce the series each day. What would Philip Eden have given to access this CETCET Central England Temperature data! 😜 As you can see from the above screen shot above I’ve added a new viewer to my Daily CET application to download, parse and display the data in tabular form and as plotted charts.
At the moment the CET series uses temperatures from the following stations:
- Rothamsted in Hertfordshire.
- Pershore in Worcestershire
- Stonyhurst in Lancashire.
Each of these site has a buddy site, so if it fails to report, the temperature from the other site can be used in its place. This happens a lot more frequently that I ever realised. The data files do include a file of eight boolean flags to identify which site were used for which day. The table below is for the CET values up to the 4 September 2024. I’ve highlighted the sites that are being used in the table in bold, and used grey text for those that aren’t. The provisional daily CET is in the 2nd from right column, and the difference column on the right, is the difference between the provisional mean and the one calculated from the raw data from stations being used. The difference is probably the adjustment applied to each stations temperature for the effects of urbanisation.
The table below is from 2004, and I think marks the point when Stonyhurst and Pershore replaced Squires Gate/Ringway and Malvern in the series. Whoever in the Met OfficeUKMO The 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 thought temperatures from a coastal site like Blackpool was a good site to represent central England beats me, although that might be down to how Manley constructed his original monthly series. I think the Stonyhurst temperature record is second only to Oxford in England in length, and had been used for many years before this.
The latest sites all have their own peculiarities as you can see from the graph below of 30 day average daily maximum temperatures. Stonyhurst is usually the coldest of the latest three sites being used to calculate daily CET values, with Pershore usually the warmest, with Rothamsted usually trailing a little behind Pershore. All this is obviously weather dependent. So the composite CET for the warmest day in the whole CET series in July 2022 ends up being in no mans land temperature wise.
Similarly in this graph of 30 day average daily minimum temperatures from 2010, Stonyhurst is usually coldest, although the three minimum series are more closely bound than the maximum. You can see that in the cold December of 2010, Pershore is fractionally colder than Stonyhurst for a while.
The table below shows how the CET series has changed at times in recent years, and how the buddy system comes into play when temperature data goes missing.
