The research I’ve seen suggests the optimum temperature range of PVC pipe is 0 degrees F to 140F. Above 140 F, you start to see deformation based on softening, and below 0 F it becomes less impact resistant. Since Schedule 40 PVC was developed to be used under high pressure, that’s what the research was investigating. On a practical level, we’ve sold
domes in Iceland, where it gets really cold, and I haven’t heard of any issues with the PVC getting brittle or cracking at low temperatures.