Expect a bit of a shock if you fill up your gas tanks in Southern California this week.
The average price of a gallon of regular gasoline in the state has jumped 23.4 cents since last Monday, according to the AAA Fuel Gauge Report.
Most of the spike has been driven by the state's southern counties.
Los Angeles and Long Beach, for example, are averaging $4.017 a gallon, up 24.8 cents over the past week.
Orange County gasoline is averaging $4.002 a gallon, up 26.1 cents since last Monday.
The Southern California averages compare to $3.859 a gallon today in San Jose and $3.723 in the region around Modesto.
So, what gives?
"Refinery maintenance," said Denton Cinquegrana, executive editor of the Oil Price Information Service. OPIS collects prices daily from more than 100,000 retail outlets across the U.S. and supplies the AAA with its averages.