I can just share my experience using Zero in cold environment. It is now -24 C at my balcony and it keeps running. It has been there for couple of years. It gets regularly -25 in winter and I don't have anything to keep it warm. In the summer it can get over 50 C at the balcony and then the Zero might crash.
Code:
$ vcgencmd measure_temptemp=-3.5'CStatistics: Posted by La-te — Thu Jan 04, 2024 12:45 am