Availability of historical precipitation data

[kantarse]

Hi all, I noticed that for many stations the historical availability of precipitation data is very limited, although temperature data is available for a very long period.

Take stations around London as an example. For 22 stations within 100km around London, I checked the earliest non-empty daily temperature (tmax) and precipitation (prcp) values since 1980. Here are the results:

station_id	station_name	country	earliest_tmax	earliest_prcp
03779	London Weather Centre	GB	1992-04-03	N/A
EGLC0	London / Abbey Wood	GB	2007-09-26	2021-01-02
03672	Northolt	GB	1980-04-23	2022-05-27
03772	London Heathrow Airport	GB	1980-01-01	1980-01-01
03781	Kenley	GB	2018-01-28	2022-05-27
EGKB0	Biggin Hill / berry's green	GB	2021-01-02	2021-01-02
03776	London Gatwick Airport	GB	1980-01-01	2022-05-27
03673	London / Chiltern Green / Newmill End / Stopsley / Lilley	GB	1988-01-31	2021-01-02
03763	Bracknell / Beaufort Park	GB	1992-03-30	2021-01-02
03683	Stansted Airport	GB	1980-01-01	2022-05-27
03768	Farnborough	GB	1988-05-02	2022-05-27
03766	Farnborough Military	GB	1980-03-03	N/A
03691	Southend-On-Sea / Sutton / Prittlewell / Rochford	GB	1988-01-29	2021-01-02
03761	Odiham	GB	1980-01-02	2021-01-02
03658	Benson	GB	1980-01-01	2021-01-02
EGTC0	Cranfield	GB	2021-01-02	2021-01-02
03876	Shoreham Airport	GB	1998-12-19	2021-01-02
EGSC0	Cambridge / Teversham	GB	2012-07-27	2021-01-02
EGVI0	Greenham Common / Shaw	GB	1983-11-08	N/A
03560	Bedford	GB	2018-01-28	2021-10-18
EGTK0	Oxford (Kidlington) / Shipton On Cherwell	GB	2021-01-02	2021-01-02
03566	Wyton Royal Air Force Base	GB	1980-01-01	N/A

So almost all of them have temperature data going way back. But many of them have precipitation data available only after 2021.

The curious thing is, notice how many of them has exactly the same start date for preciptation data: either 2021-01-02 or 2022-05-27. This cannot be a coincidence.

So this begs the question: is there some kind of cutoff date in data preparation for the precipitation data that delete the old records?