Can I drive a WRX on the factory summer tires in winter?

No. This is one of the few genuinely unsafe things you can do with an otherwise stock VB, and the all-wheel drive system actively makes it more dangerous by hiding the problem. Summer tire compound is formulated to stay pliable and grippy in warm conditions. Below roughly 45F it hardens, and grip falls away sharply. This is not a snow issue - a summer tire on a cold, dry road in January has meaningfully less grip than the same tire in July, and the driver has no obvious warning that anything has changed until they need to brake hard or turn sharply. Add snow or ice and it becomes worse than merely reduced. Summer tread patterns cannot clear snow or bite into it, and the hard compound cannot key into a cold surface. The car will not stop and it will not turn. Here is why all-wheel drive makes this trap worse rather than better. Driving a car involves accelerating, braking and turning, and all-wheel drive helps with exactly one of those. Your VB will pull confidently away from a stop on a snowy road while front-drive cars spin their wheels around you. That builds confidence the tires cannot support. The moment you need to stop at the bottom of a hill or turn into a junction, you are relying entirely on grip that is not there. Every winter, all-wheel drive cars end up in ditches facing the wrong way for exactly this reason, and the drivers are almost always surprised. What to do instead. If you see real snow and ice, fit proper winter tires as a set of four - ideally on a dedicated second wheel set so you are not remounting twice a year. If your winters are cold but rarely snowy, a quality all-season is a reasonable single-set compromise. If your winters are genuinely mild and you never approach freezing, summer tires are fine with an eye on the forecast. Swap based on sustained temperature rather than snowfall. Around 45F is the practical threshold, and waiting for the first snow means you spent weeks on a compound that was already compromised. One last thing: never mix. Winter tires on one axle and summer on the other creates wildly unbalanced grip, and on an all-wheel drive car the mismatched rolling diameters also load the centre differential. Four matching tires, always.