If the temperatures never rise above -40 my comments may be irrelavent, however this winter in the Alps temperatures fell to -15/-20 and stayed that way for days in the mountain shadows.
Frost was heavy on the wings and roof as would be expected.
The door locks could not be opened, which was just as well, as the rubber door seals would have been ripped had I opened them.
The fuel filler flap seals were ripped when I did a fuel inspection.
Fuel drains were forced open by frozen fuel, and a continuous drip of fuel ensued, adding to the block of solid holding the drains open.
Whether the battery would have turned the motors over I never found out, nut I suspec they would have been reluctant.
I was in perfect flying visability, and going no where.
This winter I am making enquiries about hangarage.
Good luck.