Wire connections can corrode if left in a humid environment, especially where temperatures change significantly. I have lost a laptop that was left in the car in the winter. Brought it in and turned it on several minutes later. Because of the temp change, moisture built up from condensation and did it in.
If I left the planes in a trailer for the winter with your conditions, I personally would put in a dehumidifier with a discharge to the outside and heater in the trailer. However, I know one guy that leaves them in the trailer all winter w/o heating and controlling the temp. I do not recall seeing any of his crashing. But then again, I don't fly with him very often and he isn't flying jets.