As I write, North West Europe is between storms Austen and Boelo, and listeners to weather forecasts are constantly regaled with threats of wind speeds up to seventy or eighty miles per hour. But frankly, I have little idea what that truly signifies. I fell to thinking. Back in the 1960s the BBC Weather Centre decided to follow the Met. Office practice and make the change to SI, since when our thermometers are graduated in °C, our visibility is expressed in metres, our rain falls by the millimetre and our snow by the centimetre. Why, then, do we cling on to m.p.h. for wind speeds?
I’m not the first to pose the question: it was examined in an article in November 2025 by “Isaac”, titled “Met Office website drops metric wind speeds”. It refers to the decision by the Meteorological Office, in 1914, to adopt metric units in place of the then current Imperial units, and its recent decision to omit all but miles per hour from its website.
A couple of years ago, we had solar panels installed on the roof of our house. It came — do I even need to tell you ? — with an app, so that you can see at any time whether the panels are generating any current, and if so, how much. The application provides all kinds of other information, including the local weather. And, would you believe it ? this shows current wind speed in metres per second (m/s) !
There has been a considerable amount of correspondence regarding the retention of Imperial measures on our roads, with all kinds of prevarication from the Department for Transport. But I see no reason why the DfT’s intransigence should prevent the BBC Weather Centre and other forecasting organizations from adopting m/s . It could be done just as easily as the change from °F to °C, using the current form followed by the new form for a set period, then reversing the order for a while, before abandoning the old form altogether. It worked with temperature, and it worked with decimal currency.
Nor is there any excuse of cost. There are no road signs to be replaced. The switch would be entirely free of charge. And there’s not much that you can say that about these days.
