[zdragnar]

You'll want winter tires on well before the air temperature hits freezing for water. Forecasts aren't that predictable, and bridges (no earth heat sink underneath) will ice over before roads do.

40 F is a good time for getting winter tires on.

As someone who lives in a humid, wet area that goes from -40 at night in winter to 100+ F in summer, I also vastly prefer Fahrenheit.

The difference between 60, 70, 80 and 90 is pretty profound with humidity, and the same is true in winter. I don't think I've ever set a thermometer to freezing or boiling, ever. All of my kitchen appliances have numbers representing their power draw.

[lye]

Well, it's been working fine for me for about 15 years, let's agree to disagree here. I would still find it easier to remember to change the tires at +1°C than whatever the hell it comes down to in Fahrenheit.

I too live in a region with 80 (Celsius) degree yearly variation (sometimes more; the maximum yearly difference I've lived through is about 90 degrees IIRC: -45 in January to +43 in July), and Fahrenheit makes absolutely no sense to me in this climate.

[rootusrootus]

> Well, it's been working fine for me for about 15 years, let's agree to disagree here.

If you want to convince yourself, go out on the road in non-winter tires when it is sub-40F, find an open space where you can experiment, and then do a panic stop. Like you might have to do if someone jumps out in front of you.

That is what convinced me to not wait until it was freezing before I put on cold weather tires.

[happyraul]

Winter tyres are less to do with freezing water and more to do with the way the tire compound in summer tires hardens/loses elasticity and therefore grip in lower temperatures, around 7 degrees Celsius.