There are all different varieties and configurations. Weather resistance to, rain, snow, ice, wind, lightning extreme cold and extreme heat and blown sand have been dealt with in the past. It's a matter of equipping them properly. Yes the can tolerate those conditions. Whether you'd desire to send a guest on them into the weather extremes is more of a guest service issue. The individual cars can be removed off the haul rope during extreme weather events to shelter them from damage, and there is likely a facility built into this system for their storage.
There is redundant drive motors on them, and that reasonable assures the lines can be cleared of people in approximately 10 minutes or less if surprise extreme weather is detected in the area.
They can be safe from lightning. That doesn't mean you want to send your average guest up in an electrical storm, not because they will be shocked by electricity, but the drama of an electrical storm with strikes near by is enough to generate a heart attack or even a panic attack. It's bad form to have your guests soil themselves.
