How much do you trust what the thermometer says in your car? Is it really 25C outside, or has the heat of the engine added a couple of degrees? Has it really hit freezing outside, or is the wind-chill making it appear colder than it is? For most of us it doesn’t matter if the car thermometer is out by a degree or two, but it is an interesting question for the Met Office.
Across the UK there are around 20 million cars that, if equipped with a Bluetooth dongle, could potentially provide real time temperature readings across the length and breadth of the country. For the Met Office this data is potentially a rich untapped resource that could significantly enhance weather forecasts.
A small trial, carried out at the University of Reading last summer, showed that car thermometers tended to produce readings that were too high when the vehicle was stationary (especially during warm weather), and too low when vehicles were travelling at speed. They also noted that temperatures tended to increase when travelling uphill. Nonetheless the data could still be useful, particularly if these systematic errors can be corrected for. Your car could become a mobile mini weather station soon.
