We have been getting a lot more than 3 days snow in recent years. Winter tyres are a definite choice but its more to do with which ones. The performance improvement is in all winter weather, not just snow; I will expect to keep them on from Nov-Mar.
The nearest temperature record available is from a location on the coast that typically is 3C higher than my home, but even here it indicates that winter tyres are better (temp. below 7C/45F) through the lower temperatures of the day for a substantial part of the year.
Nothing like the temperatures in some parts of the world but cold enough (even in sunny Scotland
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