Autos: winter tires vs summer

Self-tutoring about the differences between winter and summer tires: the tutor mentions a key one.

Apparently, 7°C is the threshold that determines which one should be driving on: below it, winter, while above, summer.

The material in summer and winter tires is different. Summer ones are made from rubber that hardens below 7°C, so they become less able to change shape with the road at such temps. Winter ones, on the other hand, can become soft enough, as the temperature rises away from 7°C, that they become prone to wear quickly. They also grip the road, in such conditions, to the extent that it may depress gas mileage.

Source:

continental-tires.com