That reading was taken after the Range Rover went tits up approaching Whitehouse. Pulled over, rang the garage and told them what the fault was. Initially they advised shutting the engine down and they'd send a recovery vehicle. I explained what the temperature was and they told me just to keep driving in. As requested, I took a picture of the display reading as Aberdeen was only -12C.
Car thermometers are usually accurate as they are mounted internal to the bodywork so as not to be affected by wind. I stopped to assist a motorist that had broken down beside the Tough junction as she said she had noticed -24C.
Before the car broke down, I took the Rottweiler out for his morning walk, the garden thermometer was reading -22C. The dog was not best pleased and tried a couple of times to run back up the road to the house.