Under what conditions is the freezing of water spontaneous? Why?
As expected after reading this answer, it's when
Clearly, when we're in a bracingly cold environment, we see a lot of frozen stuff. It's because this environment forces the freezing of that stuff.
The liquid has a tendency to freeze when the temperature is below the freezing point, and the farther below the freezing point the environment is, the greater this tendency.
That's the simple way to view it, anyway.