My car will not turn on the AC compressor even for defog if it is below 32° or somewhere in there.
I was messing with that a couple weeks ago. Freezing cold weather - no A/C for defog.
But one day it was 45° and the compressor worked fine.
As long as the AC works for summer, and
As long as warm air hits the windshield for defog mode, I would not worry too much about it. When it is 100° outside and the AC compressor is not working, THEN you have a problem.
Keep in mind, other cars may work different, but our H'* seem pretty standard to what i just said, it is my experience. Apparently, many of our experience.
I think Bill and Vital both have reason.