You obtain the best performance from your tires when they adapt to the particular road and weather conditions. As we are not able to constantly change the tires according to the changing weather and the surfaces that we drive on, we will always make a compromise. Some compromises are bigger than others.
If you live in an area that has both real summers and harsh winters, you get the best performance by having dedicated tires for both seasons and by changing the tires between each season. This will give you great performance during the summer and great performance during the winter season. You should by no means drive with summer tires in the winter or vice versa.
You can also select a compromise tire in the form of an all weather tires or an all season tires that has been approved for winter use. Then you will get good performance during the whole year, but not the greatest. However, the benefits of always being ready to drive whatever weather you will face, is a nice advantage as well as not having to change between the seasons, might also be an advantage. Do remember though that you should rotate the tires between the rear and front axles to ensure even wear between the tires.