On 15 October 1962, the United Kingdom Meteorological Office officially switched from using the Fahrenheit scale of temperature (ºF) to degrees Centigrade (ºC), or, as it had been renamed, degrees Celsius.
A bit of history
The Fahrenheit scale was proposed by Daniel Fahrenheit, a German-Polish physicist and inventor, in 1724. His invention was a mercury thermometer reliable enough to be able to record and compare the temperature of different materials. While there is some uncertainty about the origin of his decisions, it is widely accepted that he set 0º at the lowest temperature that he could achieve by mixing water, ice and ammonium chloride. The top of his scale, 90º, later amended to 96º, was his best estimate of the average body temperature of a human being.
In 1742 Swedish astronomer Anders Celsius proposed a simpler scale, setting 0º as the boiling point of water, and 100º as its freezing point. It was widely dubbed ‘centigrade’ from the Latin words for ‘hundred’ and ‘step’. The values were eventually reversed. In 1948 a body known as the International Committee for Weights and Measures renamed the scale ‘Celsius’ in honour of its deviser.
Time for a change
By the middle of the twentieth century, the Celsius scale had been widely adopted around the globe. The United Kingdom was not among the adopters. In my childhood, medical thermometers were marked in ºF with a little arrow pointing at ‘98.4’, which was considered the average ‘normal’. The same thermometers were used in hospitals.
In 1961, the UK Met Office decided to adopt Celsius for its work with Met offices worldwide. This led to the suggestion that the scale should be introduced into weather forecasting in the mainstream media. Consequently, from January 1962 weather temperatures in Fahrenheit were followed by the equivalent in Celsius. No time limit was set for discontinuing the dual use.
Change complete?
At some point, the two scales were exchanged with the temperature in Celsius being given first followed by the Fahrenheit equivalent. Then, a little later still, Fahrenheit was dropped.
But was it?
Anyone listening to the weather forecast on the BBC today will occasionally be ambushed by the unexpected inclusion of the Fahrenheit equivalent of a temperature just given. It’s not even as if it’s intended to emphasise the magnitude of the temperature; it may just be “20 degrees Celsius, that’s 68 degrees Fahrenheit.” To my mind, this is quite unnecessary.
Who is it for?
Every time I hear one of these F-bombs explode, once I have uncurled my lip and relaxed my nostrils, I ask myself, “Who are they doing that for?” Who are these people who, after more than sixty years, need to be reminded what the Fahrenheit equivalent of a forecast temperature is? Nobody under 60 who was born and has grown up in the United Kingdom will have known a system other than Celsius. It really is time that Fahrenheit became ‘Forgottenheit.’
