RC:
noone1:

Semi slicks in cold weather, if dry, is fine.

Surface cracks can appear and while they may be cosmetic at first, they can lead to serious damage later on.

So no, it is not fine (especially at temps under 0°C).

tire_zpsfbc0ec10.jpg 

Pirelli merely says it doesn't recommend Trofeos for wet or cold weather under 7C. It says grip is substantially reduced in cold weather and that they can aquaplane in the wet. Says nothing about the tires being damaged by the temperature.

https://www.pirelli.com/mediaObject/pirellityre/ww/en/catalogue/motorsport/pzero_trofeo/PZeroTrofeoR_2014_ENG/original/PZeroTrof...