Oxford has the oldest weather station in Britain, the Radcliffe Meteorological Station, dating from 1772. It is in the garden of Green College beside the Observatory building and next door to the old Radcliffe Infirmary in Woodstock Road.

It has been keeping continuous records of the city’s weather since 1815 and more spasmodic records from even before then.

In 1768, Dr Thomas Hornsby, Savilian Professor of Astronomy, approached the Radcliffe Trustees for money to build the Observatory; but he must have had a personal hobby of recording weather himself since irregular observations exist from 1767 until his death in 1810.

The money the Trustees had at their disposal came from the fortune of Dr John Radcliffe (1662-1714) who entered University College to study medicine in 1675 and went on to become London’s most fashionable — and expensive — physician. And this despite the fact that when he originally set up in practice in Oxford he had no equipment except a few phials and a skeleton.

He became physician to William III in London and by 1707 was said to have amassed £80,000 — not so much by his medical skill but by his famous wit, for which rich patients were happy to pay. For instance he once told the king, when examining the Royal swollen ankles: “I would not have your Majesty’s two legs for your three kingdoms.”

The Observatory was originally designed by Henry Keane but was completed after his death by James Wyatt. Decorations on the 108-ft octagonal tower, completed in 1794, very much reflect the earlier interest in weather on the site.

It is crowned with a copy of the Tower of the Winds, a structure that stood in ancient Athens and was built between 150-100BC by Andronicus of Cyrrhus.

The reliefs depicting the winds were carved by John Bacon the Elder, who also carved the familiar lead sculpture of Hercules and Atlas holding aloft the globe.

The Met Office’s weather station at Benson dates from 1853 — when, incidentally, the mean daily maximum temperature in December was 3.7C, not nearly as cold as this year.

The coldest December I could spot in the records was that of 1890 when the highest mean daily temperature was 0.2 C. Will this December prove to have been colder still, I ask myself?

The Met Office was originally established, under the auspices of the Board of Trade, by Robert FitzRoy (1805-1865), the captain of HMS Beagle on her second voyage (1831-1836) to Tierra del Fuego during which Charles Darwin, as the official naturalist on board, formed his ideas for The Origin of Species.

FitzRoy’s brief was to investigate the possibilities of weather forecasting, mainly to protect ships and their crews.

Ironically, Britain had a colder climate in the years before the establishment of the Met Office, namely 1550-1850, sometimes known as the Little Ice Age. I saw the River Thames frozen at Osney Lock earlier this month, but the weather cannot have been anything like as cold as that of 1813/14, the last year the Frost Fair was held on the Thames in London.

As for White Christmases, they were far more common until 1752 when Britain at last adopted the Gregorian calendar, in step with the rest of Europe. Until then, Christmas fell 12 days later, in early January, when of course we are still likely to suffer our most wintry weather.

But the Christmas of 1141 must surely have been exceptionally cold in Oxford. That year the Empress Matilda found herself holed up in Oxford Castle while her rival for the English throne, Stephen, besieged the place from two large mounds called Jews Mount and Mount Pelham.

Food was running low before she finally escaped, dressed in white so as not to show up against the snow. She crossed the frozen waters of the River Thames and Castle Mill Stream on her way to Abingdon.

All I can say is that they must have been extremely good at making white clothes in those days. Even sheep, which look white enough normally, always appear a sort of grey against a background of snow.