In summer, the road conditions in Switzerland are usually good and most mountain passes are passable. Winter tires are not compulsory during the winter months. Note, however, that you must be able to control your vehicle in any situation. If an accident occurs, liability claims will be made if your car is not equipped for the winter. It is therefore recommended to drive from October to Easter with winter tires.
Snow chains are also not compulsory. Unless this is explicitly required on a route ("snow chains mandatory" signal). Otherwise, the regulation applies analogously to winter tires: In the case of an accident, liability claims are levied if your car is not equipped for the winter.