Long Term Precipitation Trends At Oxford
By Paul Homewood
Radcliffe Meteorological Station
The Radcliffe Meteorological Station at Oxford University has been collecting weather data since 1767, and therefore offers great insights into English meteorological trends. (Officially, the Radcliffe Observatory was founded in 1772, but the first Radcliffe observer, Professor of Astronomy Thomas Hornsby, had also been keeping private records since 1767).
Not only has the data been meticulously recorded throughout, but the methodology and metadata has also been carefully documented.
A publication by JG Wallace, Meteorological Observations at Radcliffe Observatory, Oxford: 1815-1995, goes into great detail here.
I have been keeping track of their data for a while, and can now update some of the precipitation statistics.
First, annual rainfall:
The wettest year was 1852, with 1034mm. The next wettest was 2012 when 978mm fell, slightly more than the 962mm in 1960.
Driest years were 1788, 1921, 1802, 1771 and 1964.
Things appear to have got a bit wetter around the late 19thC, but there is no real sign of things changing much since then.
As I have pointed out before, the year to year variations, ie weather, utterly dwarf whatever trends there might be.
I have also obtained daily precipitation data from the Met Office, which they have for years since 1930.
Extreme daily rainfall is clearly not on the rise, either in frequency or intensity.
The three events that really do stand out were July 1968, September 1951 and June 1960.
Climate scientists keep trying to tell us that rainfall events such as these will get worse, but this is not the case in Oxford, at least.
The JG Wallace publication notes that there is some doubt whether snowfall was included in the precipitation figures in the early years.
The earliest date that this was definitely recorded as being the case was 1859, though even then it may not have been systematically done until 1926.
This could account for the early years being relatively dry, something that was also noted by two other researchers, Craddock and Smith, in 1978 (see page 42).
This actually raised a rather more fundamental issue. If snowfall was not properly accounted for at the high quality site of Radcliffe, was it properly measured at a host of lesser stations?
And can we rely on the Met Office’s national precipitation data during those years? They keep telling us that winters are getting wetter, but are they comparing like with like?