I don't know the exact specs and I have not tested. In my oppinion the battery will be the weak point. The small LiPo bag-batteries often go very weak below 0°C. You may remove it and power from external. The datasheet of the image sensor OV2640 says operating is allowed between -30°C and +70°C, stable image between 0°C and 50°C. for the other components you can find similar information in their data sheets. Make sure there is not too much humidity in air as it can condense on the electronic parts. It may help to pack the camera into thermal insulation so that it heats itself a bit over the environment. In extreme environment a small extra heating could help.