per Chevron's website FAQ they switch 11/1 and back on 2/29 in Clackamas, Multnomah, and Washington counties. Other counties are listed as well. Havent seen 93 octane in a pump around here myself.
Dave I think gospeeds wright, because I was thinking the same thing, nov threw feb, But I dont think all stations are doing it, you'll have to check out the pumps it should say on them.Just dont ask the attendents, they usally never know..lol