According to Jonathan Amos in a BBC News article about long-term temperature series from Oxford Observatory on the 6th of June:-
Temperature on this spot has been measured every single day since Sunday, 14 November 1813, making it the longest, unbroken, single-site time series of its kind in the British Isles, and one of the longest in the world.
So why is it when I download the CRUTEM data from the Met Office, a data set that includes monthly mean temperature records from over 10,000 places across the world, do I find a temperature series for Leuchars in Scotland that started in 1800?
That’s the graph, I could include a table of monthly values but it would be a mighty big screenshot, so you’ll have to take my word for it that it’s complete. The obvious thing that disqualifies Leuchars from a direct comparison with Oxford is that the site has shifted in the past, because let’s face it there was no airfield in Fife let alone anywhere else in 1800! So it maybe that observations initially started at the University in nearby St Andrews, and were transferred to Leuchars when the airfield was built in the 1940’s. Interestingly the UK has two other long temperature series included in the CRUTEM series from Orkney and Lerwick, both of which started in 1827. I wonder if the oldest data series in the world from Berlin and De Bilt which are also over 300 years long are single-site stations? I doubt it.
The one thing that I will say about mean temperature data available from the CRUTEM series is that at least it’s free, which is more than can be said of the Oxford data. As far as I can see you can freely access annual mean temperatures for Oxford since 1815, but it will cost you if you want to download all the monthly or daily values. So all these cosy pictures of an observer measuring rainfall for a cold 09 UTC observation when there’s three inch of powder snow on the ground in the BBC article don’t quite add up*. I know from personal experience in the past that they don’t answer email enquiries. If the rest of the world had the same kind of short sighted policy that Oxford have, calculating a global temperature could end up being a pretty expensive business!
*She may of course be adding a known quantity of hot water to some snow she collected from the gauge – but I doubt it, or it may have turned very mild overnight and rained – but that snow cover looks powdery, of course it may be that it’s a heated gauge – but it looks like a standard metal 5″ rain gauge to me, and if that is hot water it might end up smashing the measure!