I've noticed as winter has begun that when the car is cold that at low speeds I have a scrubbing metal on metal sound when braking at low speeds. It seems to fade as the brakes warm up, but I've never experienced this on another car.

I've heard similar scrubbing (though not as loud) on my past vehicles when it rains hard and you get a light coating of rust on the rotors that needs to be scrubbed off, but this lasts a bit longer and is noticeably more pronounced.

Anyone experienced this?

Just a guess, but there is already a lot of salt and cinders on the roads here in PA, so I imagine that you have filthy roads up there in Buffalo by now. My guess would be that you're hearing the crud that gets deposited on the rotors. Also, when you park the car this time of year, I'd expect the rotors to be covered with salt brine and therefore immediately start to corrode. Based on your description, I wouldn't worry about it. If I heard it, I may think otherwise.

My car was such a mess that I was opening the doors with just my pinky. I washed it Sunday, and it's a mess again, and the rotors are cruddy.

My guess is the light rust. Salt on the rust makes this much worse.

I've only had brake noise on our MINIs when in reverse, usually the surface rust thing. I'd get it checked out ASAP and I assume you still have warranty on the car.

I had a metal scrapping noise on the Countryman and it turned out that the ABS sensor was hanging loose and rubbing. Mechanic found this when replacing front pads/rotors/sensors. I'm pretty **** about brake replacements.

Brakes aren't something to hesitate on analyzing faults.

I've noticed that sound on pretty much every MINI I've driven if it's been kept outside in the cold for awhile. The sound always goes away after a few minutes of driving.

Thanks everyone. I've been listening carefully for it and it does appear to be going away after about 5 minutes of driving and a few regular stops.

I will add that BMWs and MINIs seem to be 'hyper-easy' to get the rear rotors rusting, and then noisy as a result. I swear all of our MINIs have been much more prone to this than any other car's we've ever owned.
However, my now gone 2012 Clubman was worse for this than my new 2017 Clubbie, both with MINI brakes stock....
Long Weekends with higher humidity and no car driving, always give me Monday Morning 'grinding' until those rotors are cleaned up with some braking/stops....

Ask the man who owns one... or TWO.