One of my external backup hard drives crashed today. I guessed that internal heat was not helping it, so I let the unit stand outside on the porch for about 20 minutes, under a temperature of 10F (-12C).
The trick worked fine! I connected it back, and it came back to life for around 30 minutes. The extra time allowed me to recover all files that I had recently stored and had not yet transferred to the secondary backup drive.
The "freezing trick" is known among geeks, see for example this post.