I've always wondered when "winter formula" gas season ends. It's never announced as far as I know, essentially a secret.
I saw this story about gas prices, but this quote caught my eye: "The region, she said, is also in the middle of annual refinery maintenance, slowing production before they switch to summer gasoline formulas. "The rest of the country doesn't move to the cleaner burning and more expensive summer fuels until late February or March," she said."
Has anyone in Oregon and/or Washington recently noticed better MPG because "winter gas" is being phased out?