Congratulations on your retirement.
There are people who have used Airstreams during ski season with some site modifications, extra equipment, copious attention to details, and realistic expectations of what to expect.
But on the whole, Airstreams are designed/engineered to be one of the best possible 3 season trailers. They are lightweight to tow, have great windows for lots of ventilation, and are equipped to work well between 90 degree high and about 25 degree low* (*overnight lows with higher daytime temps. Water systems kept from freezing by using the furnace, and a heat-taped water hose)
There are other types of RV equipment that have been engineered to be 4-season equipment. If you go to the Minnesota State Fair you can see Ice Fishing trailers that are truly rated for winter use. They have more insulation, hardly any window area, and are cozy. And heavy and dark and claustrophobic as compared to an Airstream.
Some ski areas are colder than others. I think "it depends" may be the answer to your question.
FWIW, I personally would not want to deal with the hassle of winter Airstream camping. But maybe you would. Skirting and insulation around the tires, adding a heat lamp to the underbelly section to keep things from freezing. Paying special attention to dumping and waste freezing (waste valves too). Power outages would be a worry as well.
I have heard good things about this brand of winter rated RVs--Arctic Fox.