Winter tires have a soft, pliable compound engineered to provide maximum grip on snowy and icy surfaces at freezing temperatures, but these specialized tires wear quickly and deliver longer stops on cleared roads compared to all-season tires. So, you should remove winter tires once winter is done in your area.
Of course, you cannot forecast that last rogue snow storm, but consider removing winter tires when temperatures are consistently above 40° F. That’s particularly important if you’re contemplating putting summer tires back on your car, which are not pliable in cold weather.
If you are driving on studded winter tires, the incentive to remove them might be dictated by state restrictions, as well as desire to minimize stud wear. Contact your local department of motor vehicles for guidance.