Detecting in the cold beats being inside wishing to be out detecting. Detecting in -40 could be life threatening if one is not very careful, even a tiny mistake can lead to frostbite and that is NOT fun! Also, I'd think the batteries would need to be kept right next to the body as at any temperature below what the batteries are supposed to function in they will discharge quickly under load. And being from Michigan, having a snow laden or ice covered branch of any size break off and 'clonk' a person in the head just as you've pinpointed the target could at minimum disturb the outcome of the day..........63bkpkr