If the outside is covered with snow, best if you do not even drive on summer tyres. If you live somewhere where may get snow, next tyre change get some all-seasons. If you live somewhere where snow is a given, get a separate set of winters on steel rims (ugly black ones). Else get a pair of snow socks (for tyres) in case you get stranded, after some sudden snow. Myself, I drove with my 1.0 Ibiza DSG, when the road were slushy, some snow and around -2, with summer bridgesetones Potenzas, I took it easy, used engine to brake, left plenty of distance to the other brave motorist and 'forced' it to start in 2nd gear when moving off. Shame they did away with 'winter' gear on the Autos, remembered back in the 90s I was in a car with auto, and had a snowflake button, which made the car start in 2nd gear. I'm based in London, where winters are usually 6-8 degrees, so I will stick with my summers and not go out when there is snow expected or everywhere.
I used to live in Austria where it's compulsory to have a set of winters and summers, even at -20 completely snow covered, nothing special hapens, at 6am, the tractor comes and shoves snow on the roads to the side, and every car just get on with this on their winter tyres. Even on the highway, cars still go at 80-100kmh (maybe in summer they will go 120-130kmh).