[cc439]

I guess it depends on what part of California you're talking about but all-seasons will generally outperform equivalent grade summer tires in the rain if temperatures start falling below 50-55° or so. A summer tire's grip falls off precipitously [1] when temperatures reach 40-45° but the loss of grip in that "NorCal winter" kind of weather can reduce their performance below that of all seasons. Just because they haven't lost a dangerous amount of grip doesn't mean they haven't fallen behind the grip available to a tire with a more temperature insensitive compound.

[1]: https://m.tirerack.com/tires/tiretech/techpage.jsp?techid=27...

[djakjxnanjak]

Agreed, I should have specified that all-seasons are the safe option in some parts of California. My frame of reference is the warm climates of Silicon Valley and SoCal. Summer tires could even lose traction in one of the colder nights in a San Jose winter.

[cc439]

I'm betraying my ignorance but I thought SV/SF were relatively temperate climates. Nothing like Seattle, but still 50 low to 75 high most of the time?