Hello Lee,
Sorry to hear of your problem, but no, it cannot .. ' just be the cold weather' . The photo would indicate the pads to be OK , but we are looking at just one side of one one wheel.
Could ( just could) be a small bit of road grit has be thrown up, but whatever, the braking system of the car is trying to tell you something and I would advise getting it thoroughly inspected as soon as possible.
Kind regards,
Gareth.