Unless a cloud is caused by volcanic ash, smokestack discharge, smoke from a forest fire, etc., the reason a cloud is visible is because of moisture. I guess it’s theoretically possible for a cloud to be composed of ice crystals or snow clumps?
As Willis said, the C172 is not rated for flight into known icing conditions. The FAA defines that as temps below freezing with visible moisture in the air.
The C172 only has a pitot tube warmer. That will be a great comfort to you as the wings and windscreen ice up, you lose visibility, and you plummet to the ground. At least you’ll be able to watch your dramatically decreasing altitude and know exactly how fast you were going at the moment the wings tore off!