If it hasn't showed by Nov 1st and they aren't already on, then now would be the time. The snow will be here soon enough or even icy roads,don't wait until it's too late. Better safe then sorry. Good luck.

When temps reach -7 consistently but can switch any time now 😉

I have all- weather so not switching to winter tires until we have snow to stay . But if you want to put them on wait until the temp is below 7 degrees Celsius everyday going forward .