To be the first of an inevitable wave of responses -- are you sure you need to drive for this trip?
I will preface by saying that I have driven in Europe, so I am aware that there are trips much better taken by car, and I try to refrain from providing a knee-jerk "but trains!!" response. And I am also not aware if you have disability or other personal reasons why you would need to drive.
However -- that said, Switzerland has excellent and reliable public transport, which certainly serves Zermatt, St. Moritz, the Bernese Oberland area where the Jungfraujoch is, and a large majority of other tourist destinations you are likely to be interested in. Furthermore, a select number of destinations -- notably Zermatt -- are in-fact car-free, so you will have to transfer to some form of transit or taxi for the last leg to these places anyway.
Relying on this public transport network would obviate the need to worry about road conditions, and if you are one person, likely to be at least cost-competitive if not cheaper.
Again, I understand if you specifically enjoy driving, and I have driven in both eastern (Romania) and western (Spain, France) Europe. But I would strongly recommend if you have not that you consider the alternative of public transport, which I frankly expect would be cheaper (assuming you are renting a car) and in many ways easier.