I've lived three winters with the Model S P85 in an area with winter conditions and the only problems I report are external or usability "California car" niggles, some things are not so well thought out for winter. But the battery and the drivetrain are not a problem - I don't even charge every day and I park outside. Sometimes I remember to use the app for heating the car, other times not. It has worked as well or better as any gasoline car.
Now, there are some smaller "California" issues of course that are a pain, but not any kind of showstoppers:
- The door handles do often freeze to their extended position (no problems extending them though, that's explosive if need be) as water condenses and freezes on the cavities on top of them - a better design might help here. Sometimes I've used a hair blower to unfreeze them, other times I just leave them extended.
- The folding mirrors freeze closed far more often than on any other car I've owned due to IMO a design flaw that leaves a part of the mirrors holder plane exposed on the outside when the mirror is folded, that's just inviting trouble.This means freezing and snow will create an actual barrier for the mirror unfolding. Germans also usually have plastic non-painted parts covering the folding surfaces that don't scratch so easily, you have to be careful with Tesla's mirrors. Only remedy I've found is turning folding off for the winter. I don't have to turn it off on any of my other cars.
- The charge port at first was very hard to open during winter because it froze shut and you could not force its mechanism to unlock reliably while standing near to it (so that you can push its rear end to force it open while its locking magnet unlocks). This has been remedied a bit by a software update with the ability to unlock the magnet now from the car's key remote (the button on the charge cable is not as reliable at all). So I push the charge port door's end and unlock it simultaneously to open when frozen. Newer cars have upgraded auto-closing charge port doors, maybe they work better.
- The frameless windows are a pain in the winter and more so than in Audi's I've had with similar windows. They just keep freezing into their upwards position more often, which means during winter some doors have to be closed from the outside carefully while pushing the window inwards a bit, so it fits under the aluminium trim. I've gotten used to opening and closing doors for my passengers.
- The heating of the car is not really optimized for winter conditions. I have had trouble keeping the blowers / window heaters on when parked, they keep turning off, meaning I can not reliably leave them on while cleaning the car of snow. Normally with an ICE we are taught to the car on, turn all blowers/heaters to max, and then go outside to clean the snow. With Tesla, it just keeps shutting everything down when I leave the car, so the windows remain misty and foggy on the inside when I return. They are not controllable through the app either. Obviously something one does not think of in California.
- No washers for headlights. Harder to keep them clean in poor weather. Actually a really rare omission in a car of this price in Europe. I guess this is more an American car thing perhaps than a California car thing.
Upside is the remote heating/cooling in general, it is better than the average gasoline heater/ventilator, of course, thanks to the big battery. Getting the car inside toasty is easy. Too bad the extremeties of the car are still troublesome.
Still, the biggest part, driving it, no problems. Battery does of course deplete a bit faster during winter conditions, but that's manageable.