Personally, due to experience, I wouldn't point all squeaky noises like this in newish cars to the cam belt.
I had this problem, again only in the colder months, and first decided to spray WD40 around the area of the cam belts. This obviously didn't work.
Then it got worse, so had both cam belts changed on 'professional advice'. This also didn't work.
Luckily for me I sold the car (and replaced it with Gandor) a month or so later, though (and I feel bad for this, as I'm 'usually' an honest person) took the car round the block to warm up, so the squeak wasn't audible during the test run and sale !
But, in my defence, it was a Nissan Almera which was hard to sell. And I had replaced both cam belts for no apparent reason

Still don't know what it was, but am surprised that a fairly new vehicle has this issue....