How to evaluate the assembly Storage temperature?
Since, when in storage, the PCB does not operate, you can use the Storage Temperature range.

You do have to be sure that everything on the PCB meets the Storage Temperature Tstg : -65...+125°C range though. There only needs to be one component with a smaller Temperature Range and the complete PCB will then also have this smaller Storage Temperature range.

I would especially look at components like, batteries, (electrolytic) capacitors and (LCD) displays as these often have a smaller Storage Temperature range compared to resistors, ceramic capacitors, connectors and semiconductors (chips, transistors etc.).