Most summer tires provide best performance at about 50 degrees and above. If where you are is going to stay 40 or below it might be right on the fence for putting on the snow tires. Depending on what you define "warm" as, the snow tires will obviously have a little more wear than they would in cold temps. I'm personally sticking it out on my OEM summers until it's consistently 35 or lower here...or if a large storm is on it's way. Whichever comes first.