It is 41*F for the at 2016/17 at least. It appears that has changed for the 2018/19.Stop start does not work below -10c or 14f. Also, if the cabin is not up to requested temperature.
Try page 212 of the OM.
https://my.chevrolet.com/content/da...ls/2017/Chevrolet/Cruze/2k17cruze1stPrint.pdfThe outside temperature is not in the required operating range,typically below 5 °C (41 °F) or above 50 °C (122 °F).