It's not an issue of warm or cold for me, it's an issue of once we get even 10 flakes of snow the DOT goes nuts with the sand (gravel) on the roads. During the colder months I block the
oil cooler and the bottom third of the radiator and we're cruising. The 5W-30 Mobil1 doesn't hurt either. The old Windsor makes a lot of power in the cold air!
Bob