At what temperature do you swap the stock Advans for a winter / all season solution? 50F? 40F? 30F?

 

not at any particular temperature. Once in gets snowy/icy a lot then I'll put snows on. The advans worked fine for me last year when it was really cold (15 degrees) but dry.

 

That'd be a great question to ask Yokohama, or a local shop that sells performance tires. Either should know. I plan to find out as well since a new Evo might be in the cards.

 

when it gets cold enough at night were snow is possible, then its time

 

Obviously you want to swap them when snow is on the ground. When the temperature gets cold enough the material properties of the rubber compound change. So even if it's cold and dry the Advans will still give weak performance. Like driveing on roller skates.

 

I think the driving on roller skates analogy is a bit extreme, but making the switch to all-seasons when it starts to snow in your region is a good idea.