Twin Cities gas prices jump 34 cents a gallon

Average gas prices in the Twin Cities shot up 34 cents a gallon over the past week, reaching $4.02 on Monday.

State of play: GasBuddy says prices have spiked in Minnesota, Iowa, South Dakota and other corn belt states likely because of a refinery outage.

Yes, but: Relief might be in sight because most of the nation on Saturday will be switching back to winter gasoline, which is a blend that is less expensive to produce than summer gas.

What they're saying: "We should see more price decreases for most of the nation in the weeks ahead, barring further refinery disruptions and hurricane season," Patrick De Haan, head of petroleum analysis at GasBuddy, said in a blog post. "Fall tends to bring falling gas prices, and I'm hoping this year won't be any different."