Aeotec Window/Door 7 Switch in extreme cold.

Greetings All,
I'd like to put the Window/Door 7 magnetic switch on my garage door, to be absolutely certain the door's fully closed. (The Eco Link tilt sensors are too ambiguous; the door can be almost 30% open and both upper and lower sensors show "closed.")

The Aeotec specs say operating minimum -20C (-4F). It gets considerably colder than that here. I know battery power will drop, not concerned about that. Does anyone know if the sensor suffers mechanical problems in extreme cold? Resistances drift too far? I'm asking if the unit quits working for reasons other than low battery power. (I could always power it from a wall-wart.)
Thanks for you consideration,
Ben

Unfortunately, I can't comment on temperature effects on the cold side for Aeotec devices, but I can confirm that--in situations where the temperature exceeds on the high side--units will eventually fail. I've had multiple Aeotec Smart Switches fail where I used them in an attic, and I ascribe the failures to heat.

I do have experience with harsh environments more generally. I have four outdoor devices (3 GE outdoor switches and an Everspring Illumination sensor) that have worked perfectly well for ages. I live in the Chicago area where ambient temperatures go out of bounds on both ends of the spectrum and these devices have survived.

Your mileage might vary, but I'd personally shy away from anything mission-critical in a harsh environment (exceeding recommended tolerance). I think what I'd do in your situation is put an analog switch on the door and run the wire to an indoor location, but that may not be an option for you. (I monitor my garage door with the excellent MyQ plugin.)